Exploring benefits of composition grading for forward-IV characteristics of In1−xGaxAs LEDs for cryogenic applications

Abstract

The rise of cryogenic technologies such as quantum computing [P. Platzman and M. Dykman, Science 284, 1967 (1999)] calls for semiconductor devices that can operate efficiently and with low thermal leak at low temperatures. To better understand the behavior of light-emitting diodes (LEDs) at these extreme temperatures, we derive the LED forward characteristics in the case of an InGaAs single-quantum well. We demonstrate the benefits of composition grading for increasing LED current, especially at low temperatures. This is done by deriving the optimum indium composition as a function of position. The results of the derivation are compared with COMSOL Multiphysics simulations and are found to match well.