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清华大学材料科学与工程研究院《材料科学论坛》
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联系人： 吕宁 62773015
ABSTRACT
Electron microscopy plays a major role in advancing our knowledge and understanding of III-nitride materials and devices. Analysis of AlGaN/GaN high-electron-mobility-transistor (HEMT) structures showed that small difference in the Al/N flux ratio during the growth of AlN nucleation layers by MBE had a significant impact on the microstructure and electrical properties of subsequent AlGaN/GaN heterostructures. For the InAlN/GaN HEMT structures, a vertical honeycomb structure was observed due to phase separation. Development of this honeycomb structure is likely to adversely affect the distribution of any two-dimensional electron gas at the InAlN/GaN interface and thus degrade device conductivity. Characterization of GaN quantum dot (QDs) embedded in an AlN matrix showed that the truncated pyramid GaN QDs were dislocation-free. They tended to nucleate beside edge component threading dislocations, with GaN wetting layer thickness of 2-2.5 ML in between. Observations of InN QDs and islands grown on Ga-polar GaN were consistent with a three-dimensional growth mode, with periodic arrays of misfit dislocations at the InN/GaN interface that provided strain relief for the relaxed QDs. Finally, microstructure of semipolar (1126), (1122) and non-polar (1120) GaN will also be shown.
Lin Zhou
Department of Physics,
Arizona State University, Phone: (480)-459-9135
Tempe, AZ 85287-1504 e-mail: linzhou@asu.edu
Education
Ph. D Materials Science, Arizona State University 01/2003--12/2006
Dissertation topic: Microstructure characterization of III-nitride thin films and heterostructures
Advisors: Regents’ Professor David J. Smith and Professor Martha R. McCartney GPA=3.85/4.0
B.S.E. Materials Science and Engineering, Central South University, Changsha 07/2001 GPA=4.0/4.0
Professional Experience
Assistant Research Scientist, Arizona State University 07/2007 to present
* Microstructure characterization of III-nitride materials and devices.
Postdoctoral Research Associate, Arizona State University 01/2007 to 06/2007
* Microstructure characterization of III-nitride materials and devices.
Research Assistant, Arizona State University 01/2003 to 12/2006
* Performed transmission electron microscopy (TEM) characterization on microstructure of III-nitrides heterostructures and thin films grown by molecular beam epitaxy (MBE) and metal-organic vapor phase deposition (MOCVD).
* Experienced on JEOL 2000FX, JEM-4000EX, JEOL 2010 and Philips CM200-FEG transmission electron microscopes.
Research Assistant, Central South University, Changsha, China 07/2000 to 12/2002
* analyze the structural effect of catalysis Ni25Mn5Co on diamond synthesis by scanning electron microscope (SEM) and X-ray diffraction (XRD).
* analyze the thermal stability of heat-resistant Al-Fe-V-Si alloy prepared by multi-layer spray deposition.
Invited talks/Seminars
Department of Electrical & Computer Engineering, Boston University, June, 2006.
Honors
Arizona State University
* Graduate Tuition Scholarship, 2003-2006
Central South University
* Excellent undergraduate student of Hunan Province (2001)
* Bao Steel corporation scholarship (2001)
* Hua Wei Scholarship (2000)
* Tian Xia Scholarship (1999)
Leadership
Chair, Student Union, Department of Materials Science & Engineering, Central South University, 1999-2000
Publications
1. D. F. Storm, D. S. Katzer, S. C. Binari, B. V. Shanabrook, L. Zhou, D. J. Smith, Effect of Al/N ratio during nucleation layer growth on Hall mobility and buffer leakage of molecular-beam epitaxy grown AlGaN/GaN heterostructures, Appl. Phys. Lett. 85 (2004) 3786.
2. T. Xu, A. Williams, C. Thomidi, T. D. Moustakas, L. Zhou, D. J. Smith, GaN quantum dot grown at high temperature by molecular beam epitaxy, Mater. Res. Soc. Symp. Proc., 831, 75 (2005).
3. D. S. Katzer, D. F. Storm, S. C. Binari, B. V. Shanabrook, A. Torabi, L. Zhou, D. J. Smith, Molecular beam epitaxy of InAlN/GaN heterostructures for high electron mobility transistors, J. Vac. Sci. Technol. B. 23 (2005) 1204.
4. D.F. Storm , D.S. Katzer , S.C. Binari , B.V. Shanabrook , Lin Zhou , David J. Smith, Correlation of electronic and structural properties of MBE-grown AlGaN/GaN heterostructures to Al/N flux ratio during nucleation layer growth, phys. stat. sol. (c) 7 (2005) 2212.
5. D. F. Storm, D. S. Katzer, J. A. Mittereder, S. C. Binari, B. V. Shanabrook, L. Zhou, D. J. Smith, X. Xu, D. McVey, R. P. Vaudo, G. R. Breandes, Growth and characterization of plasma-assisted molecular beam epitaxial-grown AlGaN/GaN heterostructures on free-standing hydride vapor phase epitaxy GaN substrates, J. Vac. Sci. Technol. B. 23 (2005) 1190.
6. F. Yun, Y. Fu, Y. T. Moon, Ü. Özgür, J. Q. Xie, S. Dogan, H. Morkoç, C. K. Inoki, T. S. Kuan, L. Zhou, D. J. Smith, Reduction of threading dislocations in GaN overgrowth by MOCVD on TiN porous network templates, phys. stat. sol. (a) 202 (2005) 749.
7. Y. Fu, Y. T. Moon, F. Yun, Ü. Özgür, J. Q. Xie, S. Dogan, H. Morkoç, C. K. Inoki, T. S. Kuan, Lin Zhou, David J. Smith, Effectiveness of TiN porous templates on the reduction of threading dislocations in GaN overgrowth by organometallic vapor-phase epitaxy, Appl. Phys. Lett. 86 (2005) 043108.
8. J. S. Cabalu, C. Thomidis, T. D. Moustakas, S. Riyopoulos, Lin Zhou, David J. Smith, Enhanced internal quantum efficiency and light extraction efficiency from textured GaN/AlGaN quantum wells grown by molecular beam epitaxy, J. Appl. Phys. 99 (2006) 64904.
*Also selected to appear in the Virtual Journal of Nanoscale Science & Technology April 3, 2006, Editor David Awschalom).
9. Y. Fu, F. Yun, Y. T. Moon, Ü. Özgür, J. Q. Xie, X. F. Ni, N. Biyikli, H. Morkoç, L. Zhou, D. J. Smith, C. K. Inoki, T. S. Kuan, Dislocation reduction in GaN grown on porous TiN networks by metal-organic vapor-phase epitaxy, J. Appl. Phys. 99 (2006) 033518.
10. Yiyi Wang, Ahmet S. Özcan, Karl F. Ludwig, Jr., Anirban Bhattacharyya, T. D. Moustakas, Lin Zhou, David J. Smith, Complex and incommensurate ordering in Al0.72Ga0.28N thin films grown by plasma-assisted molecular beam epitaxy, Appl. Phys. Lett. 88 (2006) 181915.
11. Y. T. Moon, C. Liu, J. Xie, X. Ni, Y. Fu, H. Morkoç, Lin Zhou, David J. Smith, In situ pendeoepitaxy of GaN using heteroepitaxial AlGaN/GaN cracks, Appl. Phys. Lett. 89 (2006) 024103.
12. L. Zhou, D. J. Smith, D. F. Storm, D. S. Katzer, S. C. Binari, B. V. Shanabrook, Effect of Al/N flux ratio during nucleation layer growth on microstructure of GaN film grown by molecular-beam epitaxy, Appl. Phys. Lett. 88 (2006) 011916.
13. L. Zhou, T. Xu, D. J. Smith, T. D. Moustakas, Microstructure of relaxed InN quantum dots grown on GaN buffer layers by molecular-beam epitaxy, Appl. Phys. Lett, 88 (2006) 231906.
*Also selected to appear in the Virtual Journal of Nanoscale Science & Technology June
19th,2006, Editor David Awschalom).
14. L. Zhou, D. J. Smith, D. S. Katzer, D. F. Storm, Observation of vertical honeycomb structure in InAlN/GaN heterostructures due to lateral phase separation, Appl. Phys. Lett. 90 (2007) 081917.
15. J. Xie, H. Morkoç, L. Zhou, and D. J. Smith, AlGaN/GaN MODFET regrown by rf-MBE on MOCVD templates, Proc. SPIE, 6473 (2007) 64730R.
16. (Invited Review) David J. Smith, Lin Zhou, and Martha R. McCartney, Structural characterization of III-nitrides using electron microscopy, Proc. SPIE, 6473 (2007) 64731J.
17. X. Ni, Ü. Özgür, A. A. Baski, H. Morkoç L. Zhou, D. J. Smith, C. A. Tran, Epitaxial lateral overgrowth of (1122) semi-polar GaN on (1100) m-plane sapphire by metalorganic chemical vapor deposition, Appl. Phys. Lett., 90, (2007) 182109.
18. D.F. Storm, D.S. Katzer, J.A. Roussos, J.A. Mittereder, R. Bass, S.C. Binari, Lin Zhou, David J. Smith, D. Hanser, E.A. Preble, K. Evans, Microwave performance and structural characterization of MBE-grown AlGaN/GaN HEMTs on low dislocation density GaN substrates, J. Crystal Growth, 305, (2007) 340.
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19. Yiyi Wang, Ahmet S. Özcan, Christopher Sanborn, Karl F. Ludwig, Anirban Bhattacharyya, Ramya Chandrasekaran, Theodore D. Moustakas, Lin Zhou, David J. Smith, Real-Time X-Ray Studies of Gallium Nitride Nanodot Formation by Droplet Heteroepitaxy, J. Appl. Phys., in press.
20. Tao Xu, Lin Zhou, Yiyi Wang, Ahmet S. Özcan, K. F. Ludwig, David J. Smith and T. D. Moustakas, Study of GaN Quantum Dot Superlattices Grown by Molecular Beam Epitaxy at High Temperature, J. Appl. Phys., in press.
21. Kristina Driscoll, Anirban Bhattacharyya, Theodore D. Moustakas, Roberto Paielle, Lin Zhou, David J. Smith, Intersuband absorption in AlN/GaN/AlGaN coupled quantum wells, Appl. Phys. Lett., 91, (2007), 141104.
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