Optimizing performance and energy consumption in GaN(n)/In x Ga 1- x N/GaN/AlGaN/GaN(p) light emitting diodes by quantum-well number and mole fraction

Abstract

Light-emitting devices (LEDs) with higher performance, lower energy demand and minimal environmental impact are needed. With wide-band gaps and high emission efficiencies, III-V nitride semiconductors are useful for LEDs in short-wavelength regions. A multiple quantum well (MQW LED), based on InGaN/GaN, is proposed. The structure involves GaN(n)/InxGa1−xN(i)/GaN(i)/AlGaN(p)/GaN(p), where GaN(n) and GaN(p) have different dopants to formulate the junction at which electric field occurs, InxGa1−xN(i) is a 3 nm-thick intrinsic quantum well with (x) as indium mole fraction, GaN(i) is barrier intrinsic layer and AlGaN(p) is a 15 nm-thick electron blocking layer (EBL). Simulation is performed by Tcad-Silvaco. Various characteristics such as current versus voltage (I-V) plots, luminosity power, band diagram, spectrum response, radiative recombination rate and electric field effect, have been investigated. By controlling the InxGa1−xN(i) number of quantum wells and their indium mole fraction (0.18 or lower), all MQW LED characteristics including radiative recombination rate, needed current, spectral power and emitted light wavelength, are optimized. Increasing (x) value improves radiative recombination rate, spectral power and band gap with lower needed current. Devices with 6 quantum wells and x = 0.16 or 0.18 exhibit best performance. For power saving and environmental purposes, optimal mole ratio is x = 0.16.