Uniformity test of the local optical thickness for GaN-based material

Based on the interference signal in the micro-photoluminescence(μ-PL) spectra,a practical method of getting local optical thickness for GaN-based material is presented.By means of analyzing the sequence energy of interference peaks,the optical thickness of the GaN-based films can be determined.The non-uniformity of the fitted parameter can correspondingly show that of the optical thickness.This can give the important information for optimizing the material growth technique.