Numerical simulation of the temperature dependence of band-edgephotoluminescence and electroluminescence in strained-Si_1-xGe_x/Si heterostructures

摘要

The temperature dependence of band-edge photoluminescence (PL) andelectroluminescence (EL) of Si_1-xGe_x/Siheterostructures was simulated using a two-carrier device simulator. Thedevice simulator was used to determine electrically and opticallyexcited carrier profiles, from which light emission was computed. Thesimulations confirmed an earlier result that PL intensity at hightemperature (>150 K) is controlled by surface recombination.Furthermore, it was found that the difference in measured temperaturedependence between PL and EL experiments is due to (i) the ELexperiments being performed at a much higher total injection rate and(ii) the heavily doped, buried contact layers in EL structures (p-i-ndiodes) effectively blocking carriers from diffusing into the substrateand away from the Si_1-xGe_x layer