In this research work, the authors have developed a highly efficient optical switch based on exotic GaN/Al0.45Ga0.55N/GaN/GaN p+-n-n−-n+ High Electron Mobility Avalanche Photodiode (HEM-APD) in 200 nm to 500 nm wavelength. The optical characteristics of a designed optical switch are analysed by developing a Quantum Modified Carrier Transport Model (QMCTM) coupled with the Monte Carlo simulation technique in terms of absorption coefficient, extinction coefficient, transmission, and reflection spectrum, gain and excess noise factor. Due to the incorporation of a small mole fraction of Al into the GAN, the 2-D Electron Gas (2-DEG) is formed at the interface between the GaN and AlGaN. The 2-DEG significantly enhances electron mobility in the active region of the device at low temperatures. Hence, the electron can travel quickly without restraint through the active region of the device. This phenomenon leads to quicker operation of the device. Additionally, the performance of the designed HEM-APD based optical switch is compared with its flat AlGaN/GaN counterpart. It is observed that the performance of the designed HEM-APD based optical switch is significantly higher compared to its counterpart. The authors have also validated the developed Quantum Modified Carrier Transport Model (QMCTM) coupled with the Monte Carlo simulation technique through experimental verification. This is the first report on development of highly efficient optical switch based on an exotic GaN/Al0.45Ga0.55N/GaN/GaN type p+-n-n–n+ High Electron Mobility Avalanche Photodiode (HEM-APD) in 200 nm to 500 nm wavelength.
Modak et al. (Mon,) studied this question.