The role of the grain boundary on persistent photoconductivity in GaN

Abstract

We present an experimental investigation on temperature, excitation intensity and spectral dependence of persistent photoconductivity (PPC) in GaN. A grain boundary induced potential barrier is predicted to be responsible for PPC. The non-exponential nature of the PPC decay has been explained by a Gaussian distribution of capture barriers, arising from the trapped charges at the grain boundary interface. The spectral dependence of the PPC suggests the origin of PPC and the yellow luminescence band may arise from the same intrinsic defect.