QUANTUM WELLS CONFIGURATION ANALYSIS ON INGAAS AND INGAN BASED NEAR-INFRARED LIGHT-EMITTING DIODE CHIPS

Abstract

An Indium Gallium Arsenide (InGaAs) and Indium Gallium Nitride (InGaN)-based-infrared light emitting diodes (lR-LEDs) were numerically analyzed based on different quantum wells (QWs) configurations in heterojunction epi-layers for optimal electro-optics performance using a simulation program known as 1DDCC program. The performance analysis is based on carrier concentration, radiative recombination, and electroluminescence. Eight structures of the two materials with different QW configurations are optimized for low current injection with high internal quantum efficiency. In InGaAs configuration, the carriers in the single quantum well (SQW) configuration are leaked at high operating current density, thus leading to a droop in the efficiency due to the reduced radiative recombination rate. The results show that the carrier confinement increase significantly enhances the radiative recombination rate for a structure with a low band gap of QW. The optimal configuration consists of 3 QWs in the epi layers and emits 900 nm peak wavelength with 0.971 internal quantum efficiency (IQE). The findings indicate that the improved carrier confinement in the active region significantly enhances the light intensity of near-infrared (NlR) LED, which is nearly twice as high in 3 QWs than in the SQW structure. Meanwhile, reducing different numbers of QWs in NlR InGaN-based light-emitting diodes was addressed to improve the IQE. The numerical results indicate a significant improvement in the internal quantum efficiency of the proposed SQW structure, achieving a critical 0.795 IQE. The improvement is associated with significantly enhanced carrier confinement due to the localization of indium in the less active region volume, leading to an improved radiative recombination rate. Additionally, the efficiency roll-off in the proposed SQW configuration is associated with QW's incomplete capture of electrons. Hence, the peak IQE of the InGaN-based configuration is obtained at a low current density of 4.5 mA cm-2. On the other hand, the InGaAs-based configuration that requires 273.3 A cm-2 will be suitable in the high current situation.