Modeling of GaN-Based Resonant Tunneling Diodes: Influence of Polarization Fields

Abstract

Resonant tunneling diodes (RTD) based on GaN/AlGaN heterojunctions should in principle show high values of peak/valley ratio due to the large conduction band discontinuities between GaN and AlGaN. Moreover, such structures have been studied to be used in quantum cascade lasers for near infrared emission. However, polarization fields can mask such benefits and make the design of RTD quite complicated. In this work, we have applied an atomistic point of view to describe current flowing in GaN-based RTD and investigate polarization issues. We used the sp3d5s* tight-binding (TB) model and a transfer matrix approach to describe the proper scattering states of the RTD system. The TB model allows us to describe the whole Brillouin zone of the semiconductors and relax all the envelope function approximations usually made for treating tunneling problems in RTDs. We observe that the effect of the polarization fields is to shift the transmission coefficient peaks while keeping a very high PVR.