Influence of residual carbon impurities in i-GaN layer on the performance of GaN-based p-i-n photodetectors

Abstract

The influence of unintentionally doped carbon impurities of i-GaN layer on the performance of GaN-based p-i-n photodetectors is investigated. The photoluminescence spectra exhibits that the carbon impurities are strongly involved in deep trap level-related yellow luminescence band. The results of secondary ion mass spectroscopy suggest that the residual carbon impurities in the i-layer have great effect on the generation of deep trap levels, and have a strong influence on the spectral responsivity and dark current of photodetectors. Thus, the way to decrease the residual carbon impurity concentration of the i-GaN layer, such as enlarging the growth pressure, can improve the performance of p-i-n photodetectors.