Research of In0.48Ga0.52P/GaAs Heterojunction Interface Properties Improvement Deposited by MOCVD

Abstract

InGaP/GaAs heterojunction layers are commonly used as semiconductor materials in GaAs solar cells. Nevertheless, challenges endure in the form of poor quality InGaP/GaAs heterojunctions. This is attributed to the diffusion of P atoms caused by the memory effect in the GaAs absorption layer, as well as the As/P exchange and H₂ etching effect in the InGaP window layer. In this work, the residual group-V source evacuation (RSE) and stabilizing method have been utilized to InGaP/GaAs heterojunction interface quality, and these effects have been investigated. The variation of process gas concentrations in metal–organic chemical vapor deposition (MOCVD) reactor is numerically studied as an indicator of H₂ etching and As/P exchange. Optimization of stabilizing and RSE period times is found to be necessary in order to achieve high-quality heterojunction, balancing the memory effect, etching effect, As/P exchange effect, and GaAs crystal quality. When the RSE and stabilizing period times are both set to 0.5 s, it is observed that the photo luminescence (PL) performance of InGaP/GaAs reached its optimal level. These studies have great significance to the fabrication of InGaP/GaAs heterojunction-based GaAs solar cell, which promotes the further development of multi-junction and high photovoltaic conversion efficiency (PCE) solar applications.