Zlatko Sitar

Kobe Steel Distinguished Professor

  • 919-515-8637
  • Research Building I 217

Prof. Sitar founded the WideBandgaps research laboratory that is focusing on bulk and thin film growth, characterization, and device development in wide bandgap semiconductors: GaN, AlN, and their alloys. He has pioneered the III-nitride MBE process through the design of a unique ECR plasma source, developed, patented, and commercialized a process for growth of AlN crystals, which is currently the only commercial high-quality AlN crystal growth process in the world (commercialized by HexaTech, Inc.), developed, patented, and commercialized epi-ready wafers and device layer growth processes on AlN wafers, which are the basis for high-efficiency deep-UV lasers and light emitting diodes, invented and patented a process for growth of III-nitride lateral polar structures via MOCVD and proposed and demonstrated novel devices based on this invention, which include lateral p-n diodes, low contact-resistance field effect transistors, quasi phase matched structures for optical frequency doubling, and superjunction-based devices.

Prof. Sitar directs the Materials Research Center at NCSU and holds joint appointments in Physics Department at NCSU and Electrical Engineering at University of Nagoya, Japan. His collaborative network spans all four inhabited continents. Based on his research, he founded HexaTech, Inc., an NCSU spin-out focusing on AlN crystal growth and wafer production and Adroit Materials, Inc., who is focusing on the development of UV light emitting devices on the AlN platform and vertical devices on native GaN substrates.

Education

Ph.D. 1990

Materials Science and Engineering

North Carolina State University

M.S. 1987

Physics

University of Ljubljana, Slovenia

B.S. 1982

Physics

University of Ljubljana, Slovenia

Research Description

Highlights of recent research accomplishments: •Developed a scalable process and equipment for growth of AlN single crystals and processes for fabrication of AlN substrates thereof. This is an extremely challenging process due to the high temperatures involved (2400°C) and materials compatibility issues. This leading work on III-nitride substrate technology is internationally recognized; many aspects of this work are patented and the technology is being commercialized. •Demonstrated the first true lasing in the UV spectral range, showing low threshold, high slope efficiency, polarization of light, narrow line, cavity modes, and far field pattern. Achieved record high IQE and low lasing threshold in AlGaN-based structures. •Following a more than 30-year-long debate in the open literature, and several years of our own research, we have finally solved the puzzle of UV absorption in AlN; this is a key finding that enables this technology to move forward. We have shown for the first time that by the manipulation of the Fermi level during the growth of wide bandgap semiconductors, we can control on what sites the point defects incorporate and what complexes form; this is an enabling technology that turns wide bandgap materials that are otherwise considered insulators into useful semiconductors. Developed a model explaining how the position of the Fermi level influences incorporation of compensating point defects. The model has been successfully used to reduce compensation by 2 orders of magnitude. •Developed an environmentally friendly, hydrogenless MOCVD process for growth of III-nitrides, which uses 100-times less ammonia and achieves films of very high quality. The process is being patented. •Developed MOCVD process for growth of GaN and AlN with controlled polarity (c+ or c-) on the same wafer; so far, others are able to grow only the c+ polar films. This process opens completely new opportunities for device design and exploitation of polarization effects in III-nitrides. Designed and demonstrated lateral polarity p-n junctions, light emitting diodes, field effect transistors, and demonstrated quasi-phase matched second harmonic generation. This work is patented. •Directly measured and explained ballistic transport in III-nitrides – developed experimental setup for precise measurement of electron energies; the first measurements of this kind in any semiconductor.

Honors and Awards

  • RJ Reynolds Award for Excellence in Research, Teaching and Extension, 2012
  • Kobe Steel Distinguished Chair, 2008
  • Entrepreneurship and Leadership Award, 2006
  • Alcoa Foundation Distinguished Engineering Award, 2004
  • Office of Naval Research MURI award, 2001

Publications

A thermodynamic supersaturation model for the growth of aluminum gallium nitride by metalorganic chemical vapor deposition
Washiyama, S., Reddy, P., Kaess, F., Kirste, R., Mita, S., Collazo, R., & Sitar, Z. (2018), JOURNAL OF APPLIED PHYSICS, 124(11). https://doi.org/10.1063/1.5045058
Doping and compensation in Al-rich AlGaN grown on single crystal AlN and sapphire by MOCVD
Bryan, I., Bryan, Z., Washiyama, S., Reddy, P., Gaddy, B., Sarkar, B., … Sitar, Z. (2018), Applied Physics Letters, 112(6).
Improvement in detection limit for time-of-flight SIMS analysis of dopants in GaN structures
Klump, A., Zhou, C. Z., Stevie, F. A., Collazo, R., & Sitar, Z. (2018), Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures, 36(3).
Nitride surface chemistry influence on band offsets at epitaxial oxide/GaN interfaces
Paisley, E. A., Brumbach, M. T., Shelton, C. T., Allerman, A. A., Atcitty, S., Rost, C. M., … Ihlefeld, J. F. (2018), Applied Physics Letters, 112(9).
On Contacts to III-nitride deep-UV emitters
Sarkar, B., Reddy, P., Klump, A., Rounds, R., Breckenridge, M. R., Haidet, B. B., … Sitar, Z. (2018),
On compensation in Si-doped AlN
Harris, J. S., Baker, J. N., Gaddy, B. E., Bryan, I., Bryan, Z., Mirrielees, K. J., … Irving, D. L. (2018), Applied Physics Letters, 112(15).
Plasma enhanced chemical vapor deposition of SiO2 and SiNx on AlGaN: Band offsets and interface studies as a function of Al composition
Reddy, P., Washiyama, S., Mecouch, W., Hernandez-Balderrama, L. H., Kaess, F., Breckenridge, M. H., … Sitar, Z. (2018), JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A, 36(6). https://doi.org/10.1116/1.5050501
Point-defect nature of the ultraviolet absorption band in AIN
Alden, D., Harris, J. S., Bryan, Z., Baker, J. N., Reddy, P., Mita, S., … Sitar, Z. (2018), Physical Review Applied, 9(5).
Probing collective oscillation of d-orbital electrons at the nanoscale
Dhall, R., Vigil-Fowler, D., Dycus, J. H., Kirste, R., Mita, S., Sitar, Z., … LeBeau, J. M. (2018), Applied Physics Letters, 112(6).
Structure of ultrathin native oxides on III-nitride surfaces
Dycus, J. H., Mirrielees, K. J., Grimley, E. D., Kirste, R., Mita, S., Sitar, Z., … LeBeau, J. M. (2018), ACS Applied Materials & Interfaces, 10(13), 10607–10611.
Thermal conductivity of GaN single crystals: Influence of impurities incorporated in different growth processes
Rounds, R., Sarkar, B., Sochacki, T., Bockowski, M., Imanishi, M., Mori, Y., … Sitar, Z. (2018), JOURNAL OF APPLIED PHYSICS, 124(10). https://doi.org/10.1063/1.5047531
Thermal conductivity of single-crystalline AIN
Rounds, R., Sarkar, B., Klump, A., Hartmann, C., Nagashima, T., Kirste, R., … Collazo, R. (2018), Applied Physics Express, 11(7).
Ultrawide-bandgap semiconductors: Research opportunities and challenges
Tsao, J. Y., Chowdhury, S., Hollis, M. A., Jena, D., Johnson, N. M., Jones, K. A., … Grotjohn, T. A. (2018), Advanced Electronic Materials, 4(1).
The influence of point defects on the thermal conductivity of AlN crystals
Rounds, R., Sarkar, B., Alden, D., Guo, Q., Klump, A., Hartmann, C., … Collazo, R. (2018), Journal of Applied Physics, 123(18).
Defect quasi Fermi level control-based C-N reduction in GaN: Evidence for the role of minority carriers
Reddy, P., Kaess, F., Tweedie, J., Kirste, R., Mita, S., Collazo, R., & Sitar, Z. (2017), Applied Physics Letters, 111(15).
Defect-free Ni/GaN Schottky barrier behavior with high temperature stability
Reddy, P., Sarkar, B., Kaess, F., Gerhold, M., Kohn, E., Collazo, R., & Sitar, Z. (2017), Applied Physics Letters, 110(1).
High free carrier concentration in p-GaN grown on AlN substrates
Sarkar, B., Mita, S., Reddy, P., Klump, A., Kaess, F., Tweedie, J., … Sitar, Z. (2017), Applied Physics Letters, 111(3).
Material considerations for the development of III-nitride power devices
Sarkar, B., Reddy, P., Kaess, F., Haidet, B. B., Tweedie, J., Mita, S., … Sitar, Z. (2017), In Gallium nitride and silicon carbide power technologies 7 (Vol. 80, pp. 29–36).
Model for the deep defect-related emission bands between 1.4 and 2.4 eV in AlN
Lamprecht, M., Jmerik, V. N., Collazo, R., Sitar, Z., Ivanov, S. V., & Thonke, K. (2017), Physica Status Solidi. B, Basic Solid State Physics, 254(8).
Nonlinear analysis of vanadium- and titanium-based contacts to Al-rich n-AlGaN
Haidet, B. B., Sarkar, B., Reddy, P., Bryan, I., Bryan, Z., Kirste, R., … Sitar, Z. (2017), Japanese Journal of Applied Physics, 56(10).
Optical nonlinear and electro-optical coefficients in bulk aluminium nitride single crystals
Majkic, A., Franke, A., Kirste, R., Schlesser, R., Collazo, R., Sitar, Z., & Zgonik, M. (2017), Physica Status Solidi. B, Basic Solid State Physics, 254(9).
Optical signatures of silicon and oxygen related DX centers in AlN
Thonke, K., Lamprecht, M., Collazo, R., & Sitar, Z. (2017), Physica Status Solidi. A, Applications and Materials Science, 214(9).
Performance improvement of ohmic contacts on Al-rich n-AlGaN grown on single crystal AlN substrate using reactive ion etching surface treatment
Sarkar, B., Haidet, B. B., Reddy, P., Kirste, R., Collazo, R., & Sitar, Z. (2017), Applied Physics Express, 10(7).
Point defect reduction in MOCVD (Al)GaN by chemical potential control and a comprehensive model of C incorporation in GaN
Reddy, P., Washiyama, S., Kaess, F., Kirste, R., Mita, S., Collazo, R., & Sitar, Z. (2017), Journal of Applied Physics, 122(24).
Slow decay of a defect-related emission band at 2.05eV in AlN: Signatures of oxygen-related DX states
Lamprecht, M., Grund, C., Bauer, S., Collazo, R., Sitar, Z., & Thonke, K. (2017), Physica Status Solidi. B, Basic Solid State Physics, 254(5).
Step-free GaN surfaces grown by confined-area metal-organic vapor phase epitaxy
Shelton, C. T., Bryan, I., Paisley, E. A., Sachet, E., Ihlefeld, J. F., Lavrik, N., … Maria, J. P. (2017), APL Materials, 5(9).
Atomically thin MoS2 narrowband and broadband light superabsorbers
Huang, L. J., Li, G. Q., Gurarslan, A., Yu, Y. L., Kirste, R., Guo, W., … Cao, L. Y. (2016), ACS Nano, 10(8), 7493–7499. https://doi.org/10.1021/acsnano.6b02195
Correlation between mobility collapse and carbon impurities in Si-doped GaN grown by low pressure metalorganic chemical vapor deposition
Kaess, F., Mita, S., Xie, J. Q., Reddy, P., Klump, A., Hernandez-Balderrama, L. H., … Sitar, Z. (2016), Journal of Applied Physics, 120(10).
Fabrication and structural properties of AlN submicron periodic lateral polar structures and waveguides for UV-C applications
Alden, D., Guo, W., Kirste, R., Kaess, F., Bryan, I., Troha, T., … Sitar, Z. (2016), Applied Physics Letters, 108(26).
High reflectivity III-nitride UV-C distributed Bragg reflectors for vertical cavity emitting lasers
Franke, A., Hoffmann, M. P., Kirste, R., Bobea, M., Tweedie, J., Kaess, F., … Sitar, Z. (2016), Journal of Applied Physics, 120(13).
High temperature and low pressure chemical vapor deposition of silicon nitride on AlGaN: Band offsets and passivation studies
Reddy, P., Washiyama, S., Kaess, F., Breckenridge, M. H., Hernandez-Balderrama, L. H., Haidet, B. B., … Sitar, Z. (2016), Journal of Applied Physics, 119(14).
Influence of high-temperature processing on the surface properties of bulk AlN substrates
Tojo, S., Yamamoto, R., Tanaka, R., Thieu, Q. T., Togashi, R., Nagashima, T., … Kumagai, Y. (2016), Journal of Crystal Growth, 446, 33–38.
On the origin of the 4.7 eV absorption and 2.8 eV emission bands in bulk AlN substrates
Alden, D., Bryan, Z., Gaddy, B. E., Bryan, I., Callsen, G., Koukitu, A., … Collazo, R. (2016), In Wide bandgap semiconductor materials and devices 17 (Vol. 72, pp. 31–40).
Point defect reduction in wide bandgap semiconductors by defect quasi Fermi level control
Reddy, P., Hoffmann, M. P., Kaess, F., Bryan, Z., Bryan, I., Bobea, M., … Sitar, Z. (2016), Journal of Applied Physics, 120(18).
Polarity control in group-III nitrides beyond pragmatism
Mohn, S., Stolyarchuk, N., Markurt, T., Kirste, R., Hoffmann, M. P., Collazo, R., … Albrecht, M. (2016), Physical Review Applied, 5(5).
Selective area epitaxy of magnesium oxide thin films on gallium nitride surfaces
Losego, M. D., Paisley, E. A., Craft, H. S., Lam, P. G., Sachet, E., Mita, S., … Maria, J. P. (2016), Journal of Materials Research, 31(1), 36–45.
Strain engineered high reflectivity DBRs in the deep UV
Franke, A., Hoffmann, P., Hernandez-Balderrama, L., Kaess, F., Bryan, I., Washiyama, S., … Sitar, Z. (2016), In Gallium nitride materials and devices xi (Vol. 9748).
Surface kinetics in AlN growth: A universal model for the control of surface morphology in III-nitrides
Bryan, I., Bryan, Z., Mita, S., Rice, A., Tweedie, J., Collazo, R., & Sitar, Z. (2016), Journal of Crystal Growth, 438, 81–89.
UV second harmonic generation in AlN waveguides with modal phase matching
Troha, T., Rigler, M., Alden, D., Bryan, I., Guo, W., Kirste, R., … Zgonik, M. (2016), Optical Materials Express, 6(6), 2014–2023.
Very slow decay of a defect related emission band at 2.4 eV in AlN: Signatures of the Si related shallow DX state
Lamprecht, M., Grund, C., Neuschl, B., Thonke, K., Bryan, Z., Collazo, R., & Sitar, Z. (2016), Journal of Applied Physics, 119(15).
The Effect of illumination power density on carbon defect configuration in silicon doped gan
Kaess, F., Reddy, P., Alden, D., Klump, A., Hernandez-Balderrama, L. H., Franke, A., … Sitar, Z. (2016), Journal of Applied Physics, 120(23).
The role of surface kinetics on composition and quality of AlGaN
Bryan, I., Bryan, Z., Mita, S., Rice, A., Hussey, L., Shelton, C., … Sitar, Z. (2016), Journal of Crystal Growth, 451, 65–71.
AlGaN devices and growth of device structures
Jones, K. A., Chow, T. P., Wraback, M., Shatalov, M., Sitar, Z., Shahedipour, F., … Tompa, G. S. (2015), Journal of Materials Science, 50(9), 3267–3307.
Charge neutrality levels, barrier heights, and band offsets at polar AlGaN
Reddy, P., Bryan, I., Bryan, Z., Tweedie, J., Washiyama, S., Kirste, R., … Sitar, Z. (2015), Applied Physics Letters, 107(9).
Fabrication of vertical Schottky barrier diodes on n-type freestanding AIN substrates grown by hydride vapor phase epitaxy
Kinoshita, T., Nagashima, T., Obata, T., Takashima, S., Yamamoto, R., Togashi, R., … Sitar, Z. (2015), Applied Physics Express, 8(6).
Growth and characterization of AlxGa1-xN lateral polarity structures
Hoffmann, M. P., Kirste, R., Mita, S., Guo, W., Tweedie, J., Bobea, M., … Sitar, Z. (2015), Physica Status Solidi. A, Applications and Materials Science, 212(5), 1039–1042.
High internal quantum efficiency in AlGaN multiple quantum wells grown on bulk AlN substrates
Bryan, Z., Bryan, I., Xie, J. Q., Mita, S., Sitar, Z., & Collazo, R. (2015), Applied Physics Letters, 106(14).
KOH based selective wet chemical etching of AlN, AlxGa1-xN, and GaN crystals: A way towards substrate removal in deep ultraviolet-light emitting diode
Guo, W., Kirste, R., Bryan, I., Bryan, Z., Hussey, L., Reddy, P., … Sitar, Z. (2015), Applied Physics Letters, 106(8).
Nanostructure surface patterning of GaN thin films and application to AlGaN/AlN multiple quantum wells: A way towards light extraction efficiency enhancement of III-nitride based light emitting diodes
Guo, W., Kirste, R., Bryan, Z., Bryan, I., Gerhold, M., Collazo, R., & Sitar, Z. (2015), Journal of Applied Physics, 117(11).
Optical characterization of Al- and N-polar AlN waveguides for integrated optics
Rigler, M., Buh, J., Hoffmann, M. P., Kirste, R., Bobea, M., Mita, S., … Zgonik, M. (2015), Applied Physics Express, 8(4).
Optical properties of aluminum nitride single crystals in the THz region
Majkic, A., Puc, U., Franke, A., Kirste, R., Collazo, R., Sitar, Z., & Zgonik, M. (2015), Optical Materials Express, 5(10), 2106–2111.
Strain dependence on polarization properties of AlGaN and AlGaN-based ultraviolet lasers grown on AlN substrates
Bryan, Z., Bryan, I., Mita, S., Tweedie, J., Sitar, Z., & Collazo, R. (2015), Applied Physics Letters, 106(23).
A conduction model for contacts to Si-doped AlGaN grown on sapphire and single-crystalline AlN
Haidet, B. B., Bryan, I., Reddy, P., Bryan, Z., Collazo, R., & Sitar, Z. (2015), Journal of Applied Physics, 117(24).
Characterization of threading dislocations in pvt-grown aln substrates via x-ray topography and ray tracing simulation
Zhou, T. Y., Raghothamachar, B., Wu, F. Z., Dalmau, R., Moody, B., Craft, S., … Sitar, Z. (2014), Journal of Electronic Materials, 43(4), 838–842.
Dependence on pressure of the refractive indices of wurtzite ZnO, GaN, and AlN
Goni, A. R., Kaess, F., Reparaz, J. S., Alonso, M. I., Garriga, M., Callsen, G., … Sitar, Z. (2014), Physical Review. B, Condensed Matter and Materials Physics, 90(4).
Exciton transitions and oxygen as a donor in m-plane AlN homoepitaxial films
Bryan, Z., Bryan, I., Bobea, M., Hussey, L., Kirste, R., Sitar, Z., & Collazo, R. (2014), Journal of Applied Physics, 115(13).
Fermi level control of compensating point defects during metalorganic chemical vapor deposition growth of Si-doped AlGaN
Bryan, Z., Bryan, I., Gaddy, B. E., Reddy, P., Hussey, L., Bobea, M., … Collazo, R. (2014), Applied Physics Letters, 105(22).
HVPE-GaN grown on MOCVD-GaN/sapphire template and ammonothermal GaN seeds: Comparison of structural, optical, and electrical properties
Sochacki, T., Bryan, Z., Amilusik, M., Bobea, M., Fijalkowski, M., Bryan, I., … Sitar, Z. (2014), Journal of Crystal Growth, 394, 55–60.
Homoepitaxial AlN thin films deposited on m-plane (1(1)over-bar00) AlN substrates by metalorganic chemical vapor deposition
Bryan, I., Bryan, Z., Bobea, M., Hussey, L., Kirste, R., Collazo, R., & Sitar, Z. (2014), Journal of Applied Physics, 116(13).
Phonon pressure coefficients and deformation potentials of wurtzite AlN determined by uniaxial pressure-dependent Raman measurements
Callsen, G., Wagner, M. R., Reparaz, J. S., Nippert, F., Kure, T., Kalinowski, S., … Sitar, Z. (2014), Physical Review. B, Condensed Matter and Materials Physics, 90(20).
Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures
Shelton, C. T., Sachet, E., Paisley, E. A., Hoffmann, M. P., Rajan, J., Collazo, R., … Maria, J. P. (2014), Journal of Applied Physics, 115(4).
Properties of AlN based lateral polarity structures
Kirste, R., Mita, S., Hoffmann, M. P., Hussey, L., Guo, W., Bryan, I., … Sitar, Z. (2014), In Physica status solidi c: current topics in solid state physics, vol 11, no 2 (Vol. 11, pp. 261–264).
Sapphire decomposition and inversion domains in N-polar aluminum nitride
Hussey, L., White, R. M., Kirste, R., Mita, S., Bryan, I., Guo, W., … Sitar, Z. (2014), Applied Physics Letters, 104(3).
Schottky contact formation on polar and non-polar AlN
Reddy, P., Bryan, I., Bryan, Z., Tweedie, J., Kirste, R., Collazo, R., & Sitar, Z. (2014), Journal of Applied Physics, 116(19).
Smooth cubic commensurate oxides on gallium nitride
Paisley, E. A., Gaddy, B. E., LeBeau, J. M., Shelton, C. T., Biegalski, M. D., Christen, H. M., … Maria, J. P. (2014), Journal of Applied Physics, 115(6).
Stimulated emission and optical gain in AlGaN heterostructures grown on bulk AlN substrates
Guo, W., Bryan, Z., Xie, J. Q., Kirste, R., Mita, S., Bryan, I., … Sitar, Z. (2014), Journal of Applied Physics, 115(10).
Surface preparation of non-polar single-crystalline AlN substrates
Bryan, I., Akouala, C. R., Tweedie, J., Bryan, Z., Rice, A., Kirste, R., … Sitar, Z. (2014), In Physica status solidi c: current topics in solid state physics, vol 11, no 3-4 (Vol. 11, pp. 454–457).
The effect of polarity and surface states on the Fermi level at III-nitride surfaces
Reddy, P., Bryan, I., Bryan, Z., Guo, W., Hussey, L., Collazo, R., & Sitar, Z. (2014), Journal of Applied Physics, 116(12).
The role of the carbon-silicon complex in eliminating deep ultraviolet absorption in AlN
Gaddy, B. E., Bryan, Z., Bryan, I., Xie, J. Q., Dalmau, R., Moody, B., … Irving, D. L. (2014), Applied Physics Letters, 104(20).
Aqueous stability of Ga- and N-polar gallium nitride
Foster, C. M., Collazo, R., Sitar, Z., & Ivanisevic, A. (2013), Langmuir, 29(1), 216–220.
Cell behavior on gallium nitride surfaces: Peptide affinity attachment versus covalent functionalization
Foster, C. M., Collazo, R., Sitar, Z., & Ivanisevic, A. (2013), Langmuir, 29(26), 8377–8384.
Comparative study of etching high crystalline quality AlN and GaN
Guo, W., Xie, J., Akouala, C., Mita, S., Rice, A., Tweedie, J., … Sitar, Z. (2013), Journal of Crystal Growth, 366, 20–25.
Direct determination of the silicon donor ionization energy in homoepitaxial AlN from photoluminescence two-electron transitions
Neuschl, B., Thonke, K., Feneberg, M., Goldhahn, R., Wunderer, T., Yang, Z., … Sitar, Z. (2013), Applied Physics Letters, 103(12).
Epitaxial PbxZr1-xTiO3 on GaN
Paisley, E. A., Craft, H. S., Losego, M. D., Lu, H., Gruverman, A., Collazo, R., … Maria, J. P. (2013), Journal of Applied Physics, 113(7).
Epitaxial lead zirconate titanate on gallium nitride (vol 113, 074107, 2013)
Paisley, E. A., Craft, H. S., Losego, M. D., Lu, H., Gruverman, A., Collazo, R., … Maria, J. P. (2013),
Excitonic emission dynamics in homoepitaxial AlN films studied using polarized and spatio-time-resolved cathodoluminescence measurements
Chichibu, S. F., Hazu, K., Ishikawa, Y., Tashiro, M., Ohtomo, T., Furusawa, K., … Sitar, Z. (2013), Applied Physics Letters, 103(14).
Fabrication and characterization of lateral polar GaN structures for second harmonic generation
Hoffmann, M. P., Gerhold, M., Kirste, R., Rice, A., Akouala, C. R., Xie, J. Q. Q., … Sitar, Z. (2013), In Quantum sensing and nanophotonic devices x (Vol. 8631).
Fermi level control of point defects during the growth of Mg-doped GaN
Bryan, Z., Hoffmann, M., Tweedie, J., Kirste, R., Callsen, G., Bryan, I., … Collazo, R. (2013), Journal of Electronic Materials, 42(5), 815–819.
Ge doped GaN with controllable high carrier concentration for plasmonic applications
Kirste, R., Hoffmann, M. P., Sachet, E., Bobea, M., Bryan, Z., Bryan, I., … Sitar, Z. (2013), Applied Physics Letters, 103(24). https://doi.org/10.1063/1.4848555
Kinase detection with gallium nitride based high electron mobility transistors
Makowski, M. S., Bryan, I., Sitar, Z., Arellano, C., Xie, J. Q., Collazo, R., & Ivanisevic, A. (2013), Applied Physics Letters, 103(1).
Lasing and longitudinal cavity modes in photo-pumped deep ultraviolet AlGaN heterostructures
Xie, J. Q., Mita, S., Bryan, Z., Guo, W., Hussey, L., Moody, B., … Sitar, Z. (2013), Applied Physics Letters, 102(17).
Performance and reliability of deep-ultraviolet light-emitting diodes fabricated on AlN substrates prepared by hydride vapor phase epitaxy
Kinoshita, T., Obata, T., Nagashima, T., Yanagi, H., Moody, B., Mita, S., … Sitar, Z. (2013), Applied Physics Express, 6(9).
Polarity control and growth of lateral polarity structures in AlN
Kirste, R., Mita, S., Hussey, L., Hoffmann, M. P., Guo, W., Bryan, I., … Sitar, Z. (2013), Applied Physics Letters, 102(18).
Preparation of free-standing GaN substrates from thick GaN layers crystallized by hydride vapor phase epitaxy on ammonothermally grown GaN seeds
Sochacki, T., Bryan, Z., Amilusik, M., Collazo, R., Lucznik, B., Weyher, J. L., … Sitar, Z. (2013), Applied Physics Express, 6(7).
Refractive index of III-metal-polar and N-polar AlGaN waveguides grown by metal organic chemical vapor deposition
Rigler, M., Zgonik, M., Hoffmann, M. P., Kirste, R., Bobea, M., Collazo, R., … Gerhold, M. (2013), Applied Physics Letters, 102(22).
Strain relaxation by pitting in AlN thin films deposited by metalorganic chemical vapor deposition
Bryan, I., Rice, A., Hussey, L., Bryan, Z., Bobea, M., Mita, S., … Sitar, Z. (2013), Applied Physics Letters, 102(6).
Universal phonon mean free path spectra in crystalline semiconductors at high temperature
Freedman, J. P., Leach, J. H., Preble, E. A., Sitar, Z., Davis, R. F., & Malen, J. A. (2013), Scientific Reports, 3.
Vacancy compensation and related donor-acceptor pair recombination in bulk AlN
Gaddy, B. E., Bryan, Z., Bryan, I., Kirste, R., Xie, J. Q., Dalmau, R., … Irving, D. L. (2013), Applied Physics Letters, 103(16).
X-ray characterization techniques for the assessment of surface damage in crystalline wafers: A model study in AlN
Bobea, M., Tweedie, J., Bryan, I., Bryan, Z., Rice, A., Dalmau, R., … Sitar, Z. (2013), Journal of Applied Physics, 113(12).
Deep-ultraviolet light-emitting diodes fabricated on AlN substrates prepared by hydride vapor phase epitaxy
Kinoshita, T., Hironaka, K., Obata, T., Nagashima, T., Dalmau, R., Schlesser, R., … Sitar, Z. (2012), Applied Physics Express, 5(12).
Lateral epitaxial overgrowth of nitrogen polar GaN on smooth nitrogen polar GaN templates by metalorganic chemical vapor deposition
Hussey, L., Mita, S., Xie, J. Q., Guo, W., Akouala, C. R., Rajan, J., … Sitar, Z. (2012), Journal of Applied Physics, 112(11).
On the origin of the 265 nm absorption band in AlN bulk crystals
Collazo, R., Xie, J. Q., Gaddy, B. E., Bryan, Z., Kirste, R., Hoffmann, M., … Sitar, Z. (2012), Applied Physics Letters, 100(19).
Optical identification of silicon as a shallow donor in MOVPE grown homoepitaxial AlN
Neuschl, B., Thonke, K., Feneberg, M., Mita, S., Xie, J. Q., Dalmau, R., … Sitar, Z. (2012), Physica Status Solidi. B, Basic Solid State Physics, 249(3), 511–515.
Optical signature of Mg-doped GaN: Transfer processes
Callsen, G., Wagner, M. R., Kure, T., Reparaz, J. S., Bugler, M., Brunnmeier, J., … Sitar, Z. (2012), Physical Review. B, Condensed Matter and Materials Physics, 86(7).
Preparation of a freestanding AIN substrate from a thick AIN layer grown by hydride vapor phase epitaxy on a Bulk AIN substrate prepared by physical vapor transport
Kumagai, Y., Kubota, Y., Nagashima, T., Kinoshita, T., Dalmau, R., Schlesser, R., … Sitar, Z. (2012), Applied Physics Express, 5(5).
Schottky barrier and interface chemistry for Ni contacted to Al0.8Ga0.2N grown on c-oriented AlN single crystal substrates
Tweedie, J., Collazo, R., Rice, A., Mita, S., Xie, J. Q., Akouala, R. C., & Sitar, Z. (2012), In Physica status solidi c: current topics in solid state physics, vol 9, no 3-4 (Vol. 9, pp. 584–587).
Structural and optical properties of carbon-doped AlN substrates grown by hydride vapor phase epitaxy using AlN substrates prepared by physical vapor transport
Nagashima, T., Kubota, Y., Kinoshita, T., Kumagai, Y., Xie, J. Q., Collazo, R., … Sitar, Z. (2012), Applied Physics Express, 5(12).
Surfactant assisted growth of MgO films on GaN
Paisley, E. A., Shelton, T. C., Mita, S., Collazo, R., Christen, H. M., Sitar, Z., … Maria, J. P. (2012), Applied Physics Letters, 101(9).
Weakly charged cationic nanoparticles induce DNA bending and strand separation
Railsback, J. G., Singh, A., Pearce, R. C., McKnight, T. E., Collazo, R., Sitar, Z., … Melechko, A. V. (2012), Advanced Materials, 24(31), 4261–.
The 7th International Workshop on Bulk Nitride Semiconductors Koyasan, Wakayama, Japan 15-20 March 2011 Preface
Freitas, J. A., Sitar, Z., Kumagai, Y., & Meissener, E. (2012), Journal of Crystal Growth, 350(1), 1–1.
265 nm light emitting diodes on AlN single crystal substrates: Growth and characterization
Collazo, R., Mita, S., Xie, J. Q., Rice, A., Tweedie, J., Dalmau, R., … Sitar, Z. (2011),
Growth and characterization of AlN and AlGaN epitaxial films on AlN single crystal substrates
Dalmau, R., Moody, B., Schlesser, R., Mita, S., Xie, J., Feneberg, M., … Sitar, Z. (2011), Journal of the Electrochemical Society, 158(5), H530–535.
On the strain in n-type GaN
Xie, J. Q., Mita, S., Hussey, L., Rice, A., Tweedie, J., LeBeau, J., … Sitar, Z. (2011), Applied Physics Letters, 99(14).
Progress on n-type doping of AlGaN alloys on AlN single crystal substrates for UV optoelectronic applications
Collazo, R., Mita, S., Xie, J. Q., Rice, A., Tweedie, J., Dalmau, R., & Sitar, Z. (2011), In Physica status solidi c: current topics in solid state physics, vol 8, no 7-8 (Vol. 8).
Sharp bound and free exciton lines from homoepitaxial AlN
Feneberg, M., Neuschl, B., Thonke, K., Collazo, R., Rice, A., Sitar, Z., … Goldhahn, R. (2011), Physica Status Solidi. A, Applications and Materials Science, 208(7), 1520–1522.
Spectroscopic measurements of the surface stoichiometry of chemical vapor deposited GaN
Craft, H. S., Rice, A. L., Collazo, R., Sitar, Z., & Maria, J. P. (2011), Applied Physics Letters, 98(8).
Strain in Si doped GaN and the Fermi level effect
Xie, J. Q., Mita, S., Rice, A., Tweedie, J., Hussey, L., Collazo, R., & Sitar, Z. (2011), Applied Physics Letters, 98(20).
Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions
Paisley, E. A., Losego, M. D., Gaddy, B. E., Tweedie, J. S., Collazo, R., Sitar, Z., … Maria, J. P. (2011), Nature Communications, 2.
Critical examination of growth rate for magnesium oxide (MgO) thin films deposited by molecular beam epitaxy with a molecular oxygen flux
Losego, M. D., Craft, H. S., Paisley, E. A., Mita, S., Collazo, R., Sitar, Z., & Maria, J. P. (2010), Journal of Materials Research, 25(4), 670–679.
Free-standing lithium niobate microring resonators for hybrid integrated optics
Koechlin, M., Sulser, F., Sitar, Z., Poberaj, G., & Gunter, P. (2010), IEEE Photonics Technology Letters, 22(4), 251–253.
Growth of AlN single crystalline boules
Herro, Z. G., Zhuang, D., Schlesser, R., & Sitar, Z. (2010), (Vol. 312, pp. 2519–2521).
Implementation of the GaN lateral polarity junction in a MESFET utilizing polar doping selectivity
Collazo, R., Mita, S., Xie, J. Q., Rice, A., Tweedie, J., Dalmau, R., & Sitar, Z. (2010), (Vol. 207, pp. 45–48).
Linear dependency of Al-mole fraction with group-III precursor flows in AlxGa1-xN (0 <= x <= 1) deposition by LP OMVPE
Rice, A., Collazo, R., Tweedie, J., Xie, J., Mita, S., & Sitar, Z. (2010), (Vol. 312, pp. 1321–1324).
Optical properties of InN grown on templates with controlled surface polarities
Kirste, R., Wagner, M. R., Schulze, J. H., Strittmatter, A., Collazo, R., Sitar, Z., … Hoffmann, A. (2010), Physica Status Solidi. A, Applications and Materials Science, 207(10), 2351–2354.
Surface preparation and homoepitaxial deposition of AlN on (0001)-oriented AlN substrates by metalorganic chemical vapor deposition
Rice, A., Collazo, R., Tweedie, J., Dalmau, R., Mita, S., Xie, J., & Sitar, Z. (2010), Journal of Applied Physics, 108(4). https://doi.org/10.1063/1.3467522
X-ray characterization of composition and relaxation of AlxGa1-xN(0 <= x <= 1) layers grown on GaN/sapphire templates by low pressure organometallic vapor phase epitaxy
Tweedie, J., Collazo, R., Rice, A., Xie, J. Q., Mita, S., Dalmau, R., & Sitar, Z. (2010), Journal of Applied Physics, 108(4).
The effect of N-polar GaN domains as Ohmic contacts
Xie, J., Mita, S., Collazo, R., Rice, A., Tweedie, J., & Sitar, Z. (2010), Applied Physics Letters, 97(12).
Advances in bulk crystal growth of AlN and GaN
Ehrentraut, D., & Sitar, Z. (2009), MRS Bulletin, 34(4), 259–265. https://doi.org/10.1557/mrs2009.76
Epitaxial Ba0.5Sr0.5TiO3-GaN heterostructures with abrupt interfaces
Losego, M. D., Kourkoutis, L. F., Mita, S., Craft, H. S., Muller, D. A., Collazo, R., … Maria, J. P. (2009), Journal of Crystal Growth, 311(4), 1106–1109. https://doi.org/10.1016/j.jcrysgro.2008.11.085
Fabrication of a GaN lateral polarity junction by metalorganic chemical vapor deposition
Mita, S., Collazo, R., & Sitar, Z. (2009), (Vol. 311, pp. 3044–3048).
Seeded growth of AlN bulk crystals in m- and c-orientation
Lu, P., Collazo, R., Dalmau, R. F., Durkaya, G., Dietz, N., Raghothamachar, B., … Sitar, Z. (2009), Journal of Crystal Growth, 312(1), 58–63. https://doi.org/10.1016/j.jcrysgro.2009.10.008
Direct observation of inversion domain boundaries of GaN on c-sapphire at sub-Angstrom resolution
Liu, F., Collazo, R., Mita, S., Sitar, Z., Pennycook, S. J., & Duscher, G. (2008), Advanced Materials, 20(11), 2162–. https://doi.org/10.1002/adma.200702522
Epitaxial growth of the metastable phase ytterbium monoxide on gallium nitride surfaces
Losego, M. D., Mita, S., Collazo, R., Sitar, Z., & Maria, J. P. (2008), Journal of Crystal Growth, 310(1), 51–56. https://doi.org/10.1016/j.jcrysgro.2007.10.002
Influence of gallium supersaturation on the properties of GaN grown by metalorganic chemical vapor deposition
Mita, S., Collazo, R., Rice, A., Dalmau, R. F., & Sitar, Z. (2008), Journal of Applied Physics, 104(1).
Modulated precursor flow epitaxial growth of AlN layers on native AlN substrates by metal-organic chemical vapor deposition
Kim, H. J., Choi, S., Yoo, D., Ryou, J. H., Dupuis, R. D., Dalmau, R. F., … Sitar, Z. (2008), Applied Physics Letters, 93(2).
Seeded growth of AlN on SiC substrates and defect characterization
Lu, P., Edgar, J. H., Cao, C., Hohn, K., Dalmau, R., Schlesser, R., & Sitar, Z. (2008), Journal of Crystal Growth, 310(10), 2464–2470. https://doi.org/10.1016/j.jcrysgro.2008.01.010
Spectroscopic analysis of the epitaxial CaO (111)-GaN (0002) interface
Craft, H. S., Collazo, R., Losego, M. D., Mita, S., Sitar, Z., & Maria, J. P. (2008), Applied Physics Letters, 92(8).
Surface water reactivity of polycrystalline MgO and CaO films investigated using x-ray photoelectron spectroscopy
Craft, H. S., Collazo, R., Losego, M. D., Sitar, Z., & Maria, J. P. (2008), Journal of Vacuum Science & Technology. A, Vacuum, Surfaces, and Films, 26(6), 1507–1510.
Thermodynamic and kinetic study of transport and reaction phenomena in gallium nitride epitaxy growth
Cai, D., Mecouch, W. J., Zheng, L. L., Zhang, H., & Sitar, Z. (2008), International Journal of Heat and Mass Transfer, 51(5-6), 1264–1280.
Three-dimensional geometry of nanometer-scale AlN pits: A new template for quantum dots?
Liu, F. D., Collazo, R., Mita, S., Sitar, Z., & Duscher, G. (2008), Advanced Materials, 20(1), 134–. https://doi.org/10.1002/adma.200701288
The influence of substrate polarity on the structural quality of InN layers grown by high-pressure chemical vapor deposition
Dietz, N., Alevli, M., Atalay, R., Durkaya, G., Collazo, R., Tweedie, J., … Sitar, Z. (2008), Applied Physics Letters, 92(4).
lu Different optical absorption edges in AlN bulk crystals grown in m- and c-orientations
Lu, P., Collazo, R., Dalmau, R. F., Durkaya, G., Dietz, N., & Sitar, Z. (2008), Applied Physics Letters, 93(13).
Band offsets and growth mode of molecular beam epitaxy grown MgO (111) on GaN (0002) by x-ray photoelectron spectroscopy
Craft, H. S., Collazo, R., Losego, M. D., Mita, S., Sitar, Z., & Maria, J.-P. (2007), Journal of Applied Physics, 102(7).
Effect of thermal environment evolution on A1N bulk sublimation crystal growth
Cai, D., Zheng, L. L., Zhang, H., Zhuang, D., Herro, Z. G., Schlesser, R., & Sitar, Z. (2007), Journal of Crystal Growth, 306(1), 39–46. https://doi.org/10.1016/j.jcrysgro.2007.04.037
Electronic high temperature characteristics of AlN
Neuburger, M., Aleksov, A., Schlesser, R., Kohn, E., & Sitar, Z. (2007), Electronics Letters, 43(10), 592–594. https://doi.org/10.1049/el:20070275
Epitaxial calcium oxide films deposited on gallium nitride surfaces
Losego, M. D., Mita, S., Collazo, R., Sitar, Z., & Maria, J. P. (2007), Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures, 25(3), 1029–1032.
Simultaneous growth of a GaN p/n lateral polarity junction by polar selective doping
Collazo, R., Mita, S., Rice, A., Dalmau, R. F., & Sitar, Z. (2007), Applied Physics Letters, 91(21).
Sublimation growth of aluminum nitride on silicon carbide substrate with aluminum nitride-silicon carbide alloy transition layer
Gu, Z., Edgar, J. H., Raghothamachar, B., Dudley, M., Zhuang, D., Sitar, Z., & Coffey, D. W. (2007), Journal of Materials Research, 22(3), 675–680. https://doi.org/10.1557/JMR.2007.0077
Synthesis of erbium-doped gallium nitride crystals by the ammonothermal route
Adekore, B. T., Callahan, M. J., Bouthillette, L., Dalmau, R., & Sitar, Z. (2007), Journal of Crystal Growth, 308(1), 71–79. https://doi.org/10.1016/j.jcrysgro.2007.07.058
X-ray photoelectron spectroscopy characterization of aluminum nitride surface oxides: Thermal and hydrothermal evolution
Dalmau, R., Collazo, R., Mita, S., & Sitar, Z. (2007), Journal of Electronic Materials, 36(4), 414–419.
The mechanism for polarity inversion of GaN via a thin AlN layer: Direct experimental evidence
Liu, F., Collazo, R., Mita, S., Sitar, Z., Duscher, G., & Pennycook, S. J. (2007), Applied Physics Letters, 91(20).
Ammonothermal synthesis of aluminum nitride crystals on group III-nitride templates
Adekore, B. T., Rakes, K., Wang, B., Callahan, M. J., Pendurti, S., & Sitar, Z. (2006), Journal of Electronic Materials, 35(5), 1104–1111. https://doi.org/10.1007/BF02692573
Characterization of bulk grown GaN and AlN single crystal materials
Raghothamachar, B., Bai, J., Dudley, M., Dalmau, R., Zhuang, D. J., Herro, Z., … Spencer, M. (2006), Journal of Crystal Growth, 287(2), 349–353. https://doi.org/10.1016/j.jcrysgro.2005.11.042
Comparative study of textured diamond films by thermal conductivity measurements
Govindaraju, N., Aleksov, A., Li, X., Okuzumi, F., Wolter, S. D., Collazo, R., … Sitar, Z. (2006), Applied Physics. A, Materials Science & Processing (Online), 85(3), 331–335. https://doi.org/10.1007/s00339-006-3697-7
Current-voltage characteristics of n/n lateral polarity junctions in GaN
Aleksov, A., Collazo, R., Mita, S., Schlesser, R., & Sitar, Z. (2006), Applied Physics Letters, 89(5).
Growth of Ga- and N- polar gallium nitride layers by metalorganic vapor phase epitaxy on sapphire wafers
Collazo, R., Mita, S., Aleksov, A., Schlesser, R., & Sitar, Z. (2006), Journal of Crystal Growth, 287(2), 586–590. https://doi.org/10.1016/j.jcrysgro.2005.10.080
Investigation of the effect of the total pressure and methane concentration on the growth rate and quality of diamond thin films grown by MPCVD
Li, X. L., Perkins, J., Collazo, R., Nemanich, R. J., & Sitar, Z. (2006), Diamond and Related Materials, 15(11-12), 1784–1788. https://doi.org/10.1016/j.diamond.2006.09.008
MgO epitaxy on GaN (0002) surfaces by molecular beam epitaxy
Craft, H. S., Ihlefeld, J. F., Losego, M. D., Collazo, R., Sitar, Z., & Maria, J. P. (2006), Applied Physics Letters, 88(21).
Molecular beam epitaxy of Sm2O3, Dy2O3, and Ho2O3 on Si (111)
Craft, H. S., Collazo, R., Sitar, Z., & Maria, J. P. (2006), Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures, 24(4), 2105–2110.
Seeded growth of AlN crystals on nonpolar seeds via physical vapor transport
Zhuang, D., Herro, Z. G., Schlesser, R., Raghothamachar, B., Dudley, M., & Sitar, Z. (2006), Journal of Electronic Materials, 35(7), 1513–1517. https://doi.org/10.1007/s11664-006-0141-x
Seeded growth of AlN on N- and Al-polar < 0 0 0 1 > AlN seeds by physical vapor transport
Herro, Z. G., Zhuang, D., Schlesser, R., Collazo, R., & Sitar, Z. (2006). Seeded growth of AlN on N- and Al-polar < 0 0 0 1 > AlN seeds by physical vapor transport. Journal of Crystal Growth, 286(2), 205–208,
Seeded growth of AlN single crystals by physical vapor transport
Zhuang, D., Herro, Z. G., Schlesser, R., & Sitar, Z. (2006), Journal of Crystal Growth, 287(2), 372–375. https://doi.org/10.1016/j.jcrysgro.2005.11.047
Silicon-on-diamond - An engineered substrate for electronic applications
Aleksov, A., Gobien, J. M., Li, X., Prater, J. T., & Sitar, Z. (2006), Diamond and Related Materials, 15(2-3), 248–253. https://doi.org/10.1016/j.diamond.2005.09.012
AlN bulk crystals grown on SiC seeds
Dalmau, R., Schlesser, R., Rodriguez, B. J., Nemanich, R. J., & Sitar, Z. (2005), Journal of Crystal Growth, 281(1), 68–74.
Bulk nitride workshop - Preface
Freitas, J. A., & Sitar, Z. (2005), Journal of Crystal Growth, 281(1), 1.
Crucible materials for growth of aluminum nitride crystals
Schlesser, R., Dalmau, R., Zhuang, D., Collazo, R., & Sitar, Z. (2005), Journal of Crystal Growth, 281(1), 75–80.
Design of an RF-heated bulk AlN growth reactor: Induction heating and heat transfer modeling
Wu, B., Noveski, V., Zhang, H., Schlesser, R., Mahajan, S., Beaudoin, S., & Sitar, Z. (2005), Crystal Growth and Design, 5(4), 1491–1498.
Fabrication and thermal evaluation of silicon on diamond wafers
Aleksov, A., Wolter, S. D., Prater, J. T., & Sitar, Z. (2005), Journal of Electronic Materials, 34(7), 1089–1094. https://doi.org/10.1007/s11664-005-0100-y
Silicon-on-diamond: An advanced silicon-on-insulator technology
Aleksov, A., Li, X., Govindaraju, N., Gobien, J. M., Wolter, S. D., Prater, J. T., & Sitar, Z. (2005), Diamond and Related Materials, 14(07-Mar), 308–313. https://doi.org/10.1016/j.diamond.2005.01.019
Transmission electron microscopy studies of the bonded SiC-SiC interface
Yushin, G. N., Kvit, A. V., & Sitar, Z. (2005, August),
Band-edge exciton states in AlN single crystals and epitaxial layers
Chen, L., Skromme, B. J., Dalmau, R. F., Schlesser, R., Sitar, Z., Chen, C., … Jiang, H. X. (2004), Applied Physics Letters, 85(19), 4334–4336. https://doi.org/10.1063/1.1818733
Growth of AlN crystals on AlN/SiC seeds by AlN powder sublimation in nitrogen atmosphere
Noveski, V., Schlesser, R., Mahajan, S., Beaudoin, S., & Sitar, Z. (2004), MRS Internet Journal of Nitride Semiconductor Research, 9(2).
Influence of relative wafer rotation on the electrical properties of the bonded SiC/SiC interface
Yushin, G. N., & Sitar, Z. (2004), Applied Physics Letters, 84(20), 3993–3995. https://doi.org/10.1063/1.1753065
Mass transfer in A1N crystal growth at high temperatures
Noveski, V., Schlesser, R., Mahajan, S., Beaudoin, S., & Sitar, Z. (2004), Journal of Crystal Growth, 264(1/3), 369–378. https://doi.org/10.1016/j.jcrysgro.2004.01.028
Model for the influence of boron impurities on the morphology of AIN grown by physical vapor transport
Brenner, D. W., Schlesser, R., Sitar, Z., Dalmau, R., Collazo, R., & Li, Y. (2004), Surface Science, 560(03-Jan), L202–206. https://doi.org/10.1016/j.susc.2004.05.003
Nanoscale GaN whiskers fabricated by photoelectrochemical etching
Grenko, J. A., Reynolds, C. L., Schlesser, R., Hren, J. J., Bachmann, K., Sitar, Z., & Kotula, P. G. (2004), Journal of Applied Physics, 96(9), 5185–5188. https://doi.org/10.1063/1.1788841
Processing and thermal properties of highly oriented diamond thin films
Wolter, S. D., Borca-Tasciuc, D., Chen, G., Prater, J. T., & Sitar, Z. (2004), Thin Solid Films, 469-70(Dec 22 2004), 105–111. https://doi.org/10.1016/j.tsf.2004.08.062
Selective etching of GaN from AlGaN/GaN and AlN/GaN structures
Grenko, J. A., Reynolds, C. L., Schlesser, R., Bachmann, K., Rietmeier, Z., Davis, R. F., & Sitar, Z. (2004), MRS Internet Journal of Nitride Semiconductor Research, 9(5).
Wafer bonding of highly oriented diamond to silicon
Yushin, G. N., Aleksov, A., Wolter, S. D., Okuzumi, F., Prater, J. T., & Sitar, Z. (2004), Diamond and Related Materials, 13(10), 1816–1821. https://doi.org/10.1016/j.diamond.2004.04.007
The growth and optical properties of large, high-quality AlN single crystals
Strassburg, M., Senawiratne, J., Dietz, N., Haboeck, U., Hoffmann, A., Noveski, V., … Sitar, Z. (2004), Journal of Applied Physics, 96(10), 5870–5876. https://doi.org/10.1063/1.1801159
Band-gap dependence of field emission from one-dimensional nanostructures grown on n-type and p-type silicon substrates
Chang, C. S., Chattopadhyay, S., Chen, L. C., Chen, K. H., Chen, C. W., Chen, Y. F., … Sitar, Z. (2003), Physical Review. B, Condensed Matter and Materials Physics, 68(12).
Bias frequency, waveform and duty-cycle effects on the bias-enhanced nucleation of epitaxial diamond
Wolter, S. D., Okuzumi, F., Prater, J. T., & Sitar, Z. (2003), Thin Solid Films, 440(02-Jan), 145–151. https://doi.org/10.1016/S0040-6090(03)00827-7
Electron energy distribution during high-field transport in AlN
Collazo, R., Schlesser, R., Roskowski, A., Miraglia, P., Davis, R. F., & Sitar, Z. (2003), Journal of Applied Physics, 93(5), 2765–2771. https://doi.org/10.1063/1.1543633
Field emission from carbon nanotubes
Collazo, R., Schlesser, R., & Sitar, Z. (2003), New Diamond and Frontier Carbon Technology, 13(5), 297–306.
Mechanisms limiting electron field emission from diamond
Schlesser, R., McClure, M. T., & Sitar, Z. (2003), New Diamond and Frontier Carbon Technology, 13(5), 285–295.
Processing routes for direct bonding of silicon to epitaxially textured diamond
Wolter, S. D., Yushin, G. N., Prater, J. T., & Sitar, Z. (2003), Diamond and Related Materials, 12(3-7), 257–261. https://doi.org/10.1016/S0925-9635(02)00392-8
Thermal conductivity of epitaxially textured diamond films
Wolter, S. D., Borca-Tasciuc, D. A., Chen, G., Govindaraju, N., Collazo, R., Okuzumi, F., … Sitar, Z. (2003), Diamond and Related Materials, 12(1), 61–64. https://doi.org/10.1016/S0925-9635(02)00248-0
AC vs. DC bias-enhanced nucleation of highly oriented diamond on silicon (100)
Wolter, S. D., Okuzumi, F., Prater, J. T., & Sitar, Z. (2002), Journal of the Electrochemical Society, 149(2), G114–117. https://doi.org/10.1149/1.1430720
Direct fusion bonding of silicon to polycrystalline diamond
Wolter, S. D., Yushin, G. N., Okuzumi, F., Stoner, B. R., Prater, J. T., & Sitar, Z. (2002), Diamond and Related Materials, 11(3-6), 482–486. https://doi.org/10.1016/S0925-9635(01)00608-2
Experimental observation of electron velocity overshoot in AlN
Collazo, R., Schlesser, R., & Sitar, Z. (2002), Applied Physics Letters, 81(27), 5189–5191. https://doi.org/10.1063/1.1534407
Growth and decomposition of bulk GaN: role of the ammonia/nitrogen ratio
Shin, H., Arkun, E., Thomson, D. B., Miraglia, P., Preble, E., Schlesser, R., … Davis, R. F. (2002), Journal of Crystal Growth, 236(4), 529–537. https://doi.org/10.1016/S0022-0248(02)00825-4
Growth of bulk AlN crystals by vaporization of aluminum in a nitrogen atmosphere
Schlesser, R., & Sitar, Z. (2002), Journal of Crystal Growth, 234(2-3), 349–353. https://doi.org/10.1016/S0022-0248(01)01720-1
High temperature nucleation and growth of GaN crystals from the vapor phase
Shin, H., Thomson, D. B., Schlesser, R., Davis, R. F., & Sitar, Z. (2002), Journal of Crystal Growth, 241(4), 404–415. https://doi.org/10.1016/S0022-0248(02)01290-3
Role of adsorbates in field emission from nanotubes
Collazo, R., Schlesser, R., & Sitar, Z. (2002), Diamond and Related Materials, 11(3-6), 769–773. https://doi.org/10.1016/S0925-9635(01)00585-4
Seeded growth of AlN bulk single crystals by sublimation
Schlesser, R., Dalmau, R., & Sitar, Z. (2002), Journal of Crystal Growth, 241(4), 416–420. https://doi.org/10.1016/S0022-0248(02)01319-2
Study of fusion bonding of diamond to silicon for silicon-on- diamond technology
Yushin, G. N., Wolter, S. D., Kvit, A. V., Collazo, R., Stoner, B. R., Prater, J. T., & Sitar, Z. (2002), Applied Physics Letters, 81(17), 3275–3277. https://doi.org/10.1063/1.1516636
Synchrotron white beam topography characterization of physical vapor transport grown AlN and ammonothermal GaN
Raghothamachar, B., Vetter, W. M., Dudley, M., Dalmau, R., Schlesser, R., Sitar, Z., … Kolis, J. W. (2002), Journal of Crystal Growth, 246(3-4), 271–280. https://doi.org/10.1016/S0022-0248(02)01751-7
Angle-dependent reflectometry as a technique for fast assessment of highly oriented diamond film quality
Wolter, S. D., Schlesser, R., Okuzumi, F., Prater, J. T., & Sitar, Z. (2001), Diamond and Related Materials, 10(11), 2092–2095. https://doi.org/10.1016/S0925-9635(01)00487-3
Frequency and duty cycle dependence on the pulsed bias-enhanced nucleation of highly oriented diamond on (100) silicon
Wolter, S. D., Okuzumi, F., Prater, J. T., & Sitar, Z. (2001), Physica Status Solidi. A, Applications and Materials Science, 186(2), 331–337.
Process optimization in the low-pressure flat flame growth of diamond
Wolter, S. D., Schlesser, R., Okuzumi, F., Prater, J. T., & Sitar, Z. (2001), Diamond and Related Materials, 10(3-7), 289–294. https://doi.org/10.1016/S0925-9635(00)00477-5
Raman spectroscopic characterization of diamond films grown in a low-pressure flat flame
Wolter, S. D., Prater, J. T., & Sitar, Z. (2001), Journal of Crystal Growth, 226(1), 88–94. https://doi.org/10.1016/S0022-0248(01)01274-X
Two field-emission states of single-walled carbon nanotubes
Collazo, R., Schlesser, R., & Sitar, Z. (2001), Applied Physics Letters, 78(14), 2058–2060. https://doi.org/10.1063/1.1361089
Characterization of dielectrics on the 'tips of needles'
Hren, J. J., Zhirnov, V. V., Sitar, Z., & Wojak, G. (2000). Characterization of dielectrics on the ’tips of needles’. Electrochemistry, 30(4), 210–215,
Energy distribution of field emitted electrons from carbon nanotubes
Schlesser, R., Collazo, R., Bower, C., Zhou, O., & Sitar, Z. (2000), Diamond and Related Materials, 9(3-6), 1201–1204.
Growth and characterization of GaN single crystals
Balkas, C. M., Sitar, Z., Bergman, L., Shmagin, I. K., Muth, J. F., Kolbas, R., … Davis, R. F. (2000), Journal of Crystal Growth, 208(1-4), 100–106. https://doi.org/10.1016/S0022-0248(99)00445-5
Hot electron transport in AlN
Collazo, R., Schlesser, R., Roskowski, A., Davis, R. F., & Sitar, Z. (2000), Journal of Applied Physics, 88(10), 5865–5869. https://doi.org/10.1063/1.1318386
Effect of nitrogen incorporation on electron emission from chemical vapor deposited diamond
Park, M., Sowers, A. T., Rinne, C. L., Schlesser, R., Bergman, L., Nemanich, R. J., … Choi, W. B. (1999), Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures, 17(2), 734–739.
The influences of reactant composition and substrate material on the combustion synthesis of diamond
Wolden, C. A., Draper, C. E., Sitar, Z., & Prater, J. T. (1999), Journal of Materials Research, 14(1), 259–269. https://doi.org/10.1557/JMR.1999.0038
Coalesced oriented diamond films on nickel
Yang, P. C., Wolden, C. A., Liu, W., Schlesser, R., Davis, R. F., Prater, J. T., & Sitar, Z. (1998), Journal of Materials Research, 13(5), 1120–1123. https://doi.org/10.1557/JMR.1998.0157
Electron emission characteristics of GaN pyramid arrays grown via organometallic vapor phase epitaxy
Ward, B. L., Nam, O. H., Hartman, J. D., English, S. L., McCarson, B. L., Schlesser, R., … Nemanich, R. J. (1998), Journal of Applied Physics, 84(9), 5238–5242. https://doi.org/10.1063/1.368775
Electron emission mechanism from cubic boron nitride-coated molybdenum emitters
McCarson, B. L., Schlesser, R., McClure, M. T., & Sitar, Z. (1998), Applied Physics Letters, 72(22), 2909–2911. https://doi.org/10.1063/1.121492
Electron energy distribution of diamond-coated field emitters
Choi, W. B., Schlesser, R., Wojak, G., Cuomo, J. J., Sitar, Z., & Hren, J. J. (1998), Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures, 16(2), 716–719.
Field emission energy distribution analysis of cubic-BN-coated Mo emitters: Nonlinear behavior
McCarson, B. L., Schlesser, R., & Sitar, Z. (1998), Journal of Applied Physics, 84(6), 3382–3385. https://doi.org/10.1063/1.368496
Field emission energy distribution analysis of wide-band-gap field emitters
Schlesser, R., McCarson, B. L., McClure, M. T., & Sitar, Z. (1998), Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures, 16(2), 689–692.
Flat-flame diamond CVD: the effect of pressure and operating conditions for specific applications
Wolden, C. A., Davis, R. F., Sitar, Z., & Prater, J. T. (1998), Diamond and Related Materials, 7(2-5), 133–138. https://doi.org/10.1016/S0925-9635(97)00206-9
Heteroepitaxial nucleation of diamond on nickel
Sitar, Z., Liu, W., Yang, P. C., Wolden, C. A., Schlesser, R., & Prater, J. T. (1998), Diamond and Related Materials, 7(2-5), 276–282. https://doi.org/10.1016/S0925-9635(97)00244-6
Mechanisms of field emission from diamond coated Mo emitters
Schlesser, R., McClure, M. T., McCarson, B. L., & Sitar, Z. (1998), Diamond and Related Materials, 7(2-5), 636–639. https://doi.org/10.1016/S0925-9635(97)00290-2
Structural and electronic properties of boron nitride thin films containing silicon
Ronning, C., Banks, A. D., McCarson, B. L., Schlesser, R., Sitar, Z., Davis, R. F., … Nemanich, R. J. (1998), Journal of Applied Physics, 84(9), 5046–5051. https://doi.org/10.1063/1.368752
Surface melting in the heteroepitaxial nucleation of diamond on Ni
Yang, P. C., Liu, W., Schlesser, R., Wolden, C. A., Davis, R. F., Prater, J. T., & Sitar, Z. (1998), Journal of Crystal Growth, 187(1), 81–88. https://doi.org/10.1016/S0022-0248(97)00854-3
Transmission electron microscoanalysis of the oriented diamond growth on nickel substrates
Liu, W., Yang, P. C., Wolden, C. A., Davis, R. F., Prater, J. T., & Sitar, Z. (1998), Journal of Applied Physics, 83(12), 7658–7663. https://doi.org/10.1063/1.367885
The influence of nitrogen addition on the morphology, growth rate, and Raman spectra of combustion grown diamond
Wolden, C. A., Draper, C. E., Sitar, Z., & Prater, J. T. (1998), Diamond and Related Materials, 7(8), 1178–1183. https://doi.org/10.1016/S0925-9635(98)00172-1
Control of diamond heteroepitaxy on nickel by optical reflectance
Yang, P. C., Schlesser, R., Wolden, C. A., Liu, W., Davis, R. F., Sitar, Z., & Prater, J. T. (1997), Applied Physics Letters, 70(22), 2960–2962. https://doi.org/10.1063/1.118756
Dielectric, pyroelectric and structural properties of LiTaO3 thin films grown on silicon by a modified molecular beam epitaxy
Tao, Y., Gitmans, F., Sitar, Z., Pierhofer, H., Kundig, A., Gamboni, I., & Gunter, P. (1997), Ferroelectrics, 201(1-4), 245–253. https://doi.org/10.1080/00150199708228374
Electrical characterization of diamond and graphite coated Mo field emitters
McClure, M. T., Schlesser, R., McCarson, B. L., & Sitar, Z. (1997), Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures, 15(6), 2067–2071.
Energy distribution of field emitted electrons from diamond coated molybdenum tips
Schlesser, R., McClure, M. T., Choi, W. B., Hren, J. J., & Sitar, Z. (1997), Applied Physics Letters, 70(12), 1596–1598. https://doi.org/10.1063/1.118626
Gas-source molecular beam epitaxy of III-V nitrides
Davis, R. F., Paisley, M. J., Sitar, Z., Kester, D. J., Ailey, K. S., Linthicum, K., … Kern, R. S. (1997), Journal of Crystal Growth, 178(1/2), 87–101. https://doi.org/10.1016/S0022-0248(97)00077-8
Growth of AlN and GaN thin films via OMVPE and gas source MBE and their characterization
Davis, R. F. (1997), Solid-State Electronics, 41(2), 129–134. https://doi.org/10.1016/S0038-1101(96)00152-9
Highly oriented diamond deposited using a low pressure flat flame
Wolden, C. A., Han, S.-K., McClure, M. T., Sitar, Z., & Prater, J. T. (1997), Materials Letters, 32(1), 9–12. https://doi.org/10.1016/S0167-577X(97)00003-7
In situ mass spectrometry during diamond chemical vapor deposition using a low pressure flat flame
Wolden, C. A., Davis, R. F., Sitar, Z., & Prater, J. T. (1997), Journal of Materials Research, 12(10), 2733–2742. https://doi.org/10.1557/JMR.1997.0364
Low-temperature deposition of optically transparent diamond using a low-pressure flat flame
Wolden, C. A., Davis, R. F., Sitar, Z., & Prater, J. T. (1997), Diamond and Related Materials, 6(12), 1862–1867. https://doi.org/10.1016/S0925-9635(97)00155-6
Optical metastability in bulk GaN single crystals
Shmagin, I. K., Muth, J. F., Lee, J. H., Kolbas, R. M., Balkas, C. M., Sitar, Z., & Davis, R. F. (1997), Applied Physics Letters, 71(4), 455–457. https://doi.org/10.1063/1.119577
Photoluminescence from mechanically milled Si and SiO(2) powders
Shen, T. D., Shmagin, I. K., Koch, C. C., Kolbas, R. M., Fahmy, Y., Bergman, L., … Quan, M. X. (1997), Physical Review. B, Condensed Matter and Materials Physics, 55(12), 7615–7623.
Sublimation growth and characterization of bulk aluminum nitride single crystals
Balkas, C. M., Sitar, Z., Zheleva, T. S., Bergman, L., Nemanich, R. J., & Davis, R. F. (1997), Journal of Crystal Growth, 179(3-4), 363–370. https://doi.org/10.1016/S0022-0248(97)00160-7
Growth of cubic phase gallium nitride by modified molecular-beam epitaxy
Paisley, M. J., Sitar, Z., Posthill, J. B., & Davis, R. F. (1989), Journal of Vacuum Science & Technology. A, Vacuum, Surfaces, and Films, 7(3), 701–705.

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