High-temperature optical characterization of wide band gap light emitting diodes and photodiodes for future power module application

Abstract

A systematic study of wide bandgap (WBG) based light emitting diodes (LEDs) and photodiodes (PDs) were conducted for the assessment of modular integration of optoelectronic devices into power modules. The temperature dependence of the photoluminescence (PL) efficiency of Indium gallium nitride/Gallium nitride (InGaN/GaN) multiple quantum wells (MQWs) material was studied from 10 to 800 K. The photoluminescence efficiency is calculated using the power law relation connecting the integrated photoluminescence signal and the excitation pump power. A peak PL efficiency of 43.97 % was recorded at 800 K. Electroluminescence (EL) study was conducted on Gallium nitride (GaN) based LEDs in the temperature range of 300 – 800 K. An intensity drop of three orders of magnitude is recorded at 800 K as compared to room temperature. The full width half maximum (FWHM) of the spectra was also calculated from the EL measurements. The S-shaped shift of FWHM at high temperature indicates a strong localization effect. High-temperature spectral response analysis of 4H-Silicon carbide (4H-SiC) pn-junction photodiode is performed at zero voltage bias condition. Enhancement of spectral response is observed at higher wavelengths due to increased phonon population at higher temperatures.