Resonant tunneling structures to significantly reduce the voltage drop in contacting pZnSe layer in blue-green lasers: simulation of voltage-current behavior

摘要

Abstract: This paper describes the usage of a novel asymmetric resonant tunneling structure (RTS) to obtain low voltage drop contacts to pZnSe and other wide energy gap semiconductors. Generally, the contact to p-ZnSe is achieved by the formation of a Schottky barrier or by forming a graded layer interface to pZnSe. These techniques have been employed in fabricating ZnSe based blue-green lasers, reported during the past few years using structures grown by Molecular Beam Epitaxy. Most of these approaches result in contact voltage drops ranging from 6-30 volts for a typical current above laser threshold. In the case of pGaAs-pZnSe (or pZnCdSe) interface, the presence of a large valence energy band offset results in high voltage drop due to a rectifying interface. The use of asymmetric resonant tunneling structure(s) at these heterointerfaces is shown to result in a significantly low (0.4 volts) voltage drops at current densities above threshold ($APEQ 600 A/Cm$+2$/). The incorporation of asymmetric resonant tunneling structures is also proposed for lasers on InP substrates. It is a generic technique which can be used for realizing low resistance contacts in material systems where standard contact techniques produce poor results. This technique is applicable for both p- and n-type heterojunction interfaces.!18