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Research Interests

Dr. Mikhail Reshchikov
Assistant Professor

Point defects in semiconductors. Optical properties of wide-bandgap semiconductors.

Wide-bandgap semiconductors are widely used in modern electronic and optical devices such as laser diodes, light-emitting diodes, UV detectors, high-power high-frequency transistors.  Point defects strongly affect electrical and optical properties of these devices. Currently concentration of uncontrolled impurities and native point defects in the state-of-art wide-bandgap semiconductors, such as GaN, AlN, and ZnO is well above 1015cm-3. Typical examples of point defects are impurity atoms, isolated vacancies, and complexes including two or more defect components such as the gallium vacancy-oxygen complex in GaN. Most of the defects in wide-bandgap semiconductors remain unidentified in spite of serious effort made in this field in recent years.

Photoluminescence is a very promising method for investigation of point defects, especially in wide-bandgap semiconductors. It allows to identify a defect, to estimate its concentration, local symmetry, its ability to capture holes and electrons, to find some other important characteristics. Some defects are metastable, meaning that under different experimental conditions they may have different symmetry, energy, and other properties. Surface states also significantly affect the properties of semiconductors and related devices. Photoluminescence is often able to reveal the manifestation of the surface states. 

  • M. A. Reshchikov, D. Huang, F. Yun, P. Visconti, L. He, J. Jasinski, Z. Liliental-Weber, R. J. Molnar, and H. Morkoç, Unusual luminescence lines in GaN, J. Appl. Phys. 94, 5623 (2003).

  • M. A. Reshchikov, M. Zafar Iqbal, H. Morkoç, S. S. Park, and K. Y. Lee, Long-lasting photoluminescence in freestanding GaN templates, Appl. Phys. Lett. 83, 266 (2003).

  • M. A. Reshchikov, H. Morkoc, S. S. Park, and K. Y. Lee, Two charge states of dominant acceptor in unintentionally doped GaN: Evidence from photoluminescence study, Appl. Phys. Lett. 81, 4970 (2002).

  • M. A. Reshchikov and R. Y. Korotkov, Analysis of the temperature and excitation intensity dependencies of photoluminescence in undoped GaN films, Phys. Rev. B 64, 115205 (2001).

  • M. A. Reshchikov, H. Morkoç, S. S. Park, and K. Y. Lee, Yellow and green luminescence in freestanding GaN template, Appl. Phys. Lett. 78, 3041 (2001).

  • M. A. Reshchikov, H. Morkoç, S. S. Park, and K. Y. Lee, Transient photoluminescence of defect transitions in freestanding GaN, Appl. Phys. Lett. 78, 2882 (2001).

 

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