Effects of gamma radiation on the electrical properties of InAs/InGaAs quantum dot-based laser structures grown on GaAs and Si substrates by molecular beam epitaxy

This study investigates the impact of gamma radiation on the electrical properties of InAs/InGaAs quantum dot-based laser structures grown on both GaAs (Sample A) and Si (Sample B) substrates using molecular beam epitaxy. The research explores the electrical characteristics of the lasers before and after being exposed to gamma radiation employing current-voltage (I-V), capacitance-voltage (C-V), deep level transient spectroscopy (DLTS) and Laplace DLTS techniques. The results show that the electrical properties of the lasers change due to gamma radiation exposure, and the extent of the change depends on the substrate used for growth. The I-V results revealed that the ideality factor (n) and built-in voltage were increased in Sample A and Sample B after radiation. Nonetheless, the series resistance (R_s) at room temperature decreased in both samples after radiation. Overall, this study provides valuable insights into the effects of gamma radiation on the electrical properties of InAs/InGaAs quantum dot lasers and highlights the importance of considering substrate materials in the design of radiation-hardened electronic devices.