Comparison of light emission from room temperature light emitting diodes with InAs active regions grown by LPE

Abstract

InAs and InAsSbP are promising materials for the fabrication of mid-infrared light sources for use in solid state gas sensors. In this paper, we report work on n-i-p and p-i-n. InAs light emitting diode structures grown using liquid phase epitaxy (LPE) on InAs substrates. These homoepitaxial diodes were compared to double heterojunction InAsSbP/InAs LEDs with InAs active regions. Room temperature emission at wavelengths between 3.3 µm and 3.7 µm (dependent on structure) was readily obtained. Electroluminescence spectra of these devices are presented, and a comparison with photoluminescence spectra of the epitaxial material is used to determine the region of the diode giving rise to the light emission. At room temperature, in the double heterojunction LEDs, the light emission was observed to originate from the InAs active region. However, in the homoepitaxial LEDs, the light was generated both in the undoped and p+ regions of the device, depending on the precise structure.