Defects in Semiconductors
February 3, 2017
Michael Reshchikov, Department of Physics, Virginia Commonwealth University
In spite of many years of research, point defects with deep levels in semiconductors are still not well understood. The defects create unwanted paths of charge carriers recombination, which leads to premature breakdown in high-power electronic devices, reduces efficiency of the light-emitting devices and shortens their lifetime. Gallium Nitride (GaN) is a relatively new semiconductor, which is currently used in blue light emitting devices (LEDs, laser diodes), and is expected to transform all lighting technology in near future. Point defects in GaN can be studied by several techniques, among which photoluminescence (PL) appears to be the strongest tool.
In this presentation, the history of investigations into point defects in semiconductors will be reviewed, including showing interesting examples where incorrect theoretical predictions caused biased and incorrect explanations of experimental results and vice versa. A simple configuration coordinate model will be used to explain PL spectra from defects. The PL results will be compared with theoretical predictions and experimental results obtained by using other techniques, such as deep-level transient spectroscopy (DLTS) or positron annihilation spectroscopy (PAS).