Enhanced optical gain characteristics of InAlN/δ-GaN/InAlN nanoscale-heterostructure for D-UV applications

摘要

Most of the Ill-nitride heterostructures have exhibited type-I band alignment producing low optical gain due to which there is a serious restriction on the device design flexibility; hence further studies are required to investigate the technique for improvement of the optical gain characteristics. Here, this paper reports the enhancement of optical gain of Ill-nitride heterostructure, particularly, InAlN/InAIN nano-scale heterostructure by introducing an ultra-thin layer of GaN material in the central region of the heterostructure. The introduction of GaN layer causes the electron-hole wave functions to be localized strongly in the central part of the QW (quantum well) due to which a very large optical gain is achieved in, so called, InAlN/δ-GaN/InAlN nanoscale-heterostructure. According to the simulation results, for modified InAlN/δ-GaN/InAlN nano-scale heterostructure the TE (Transverse Electric) optical gain achieved in the D-UV (deep-ultra-violet) region is more than three times greater than the optical gain of the conventional III-nitride heterostructures. Moreover, the achieved gain has further been observed to be enhanced significantly by the application of DC (direct current) electric field on the proposed heterostructure. Due to very high UV optical gain, the InAlN/δ-GaN/InAlN nano-scale heterostructure can be a promising heterostructure functioning in D-UV optical laser diodes.