Lateral diffusion of photogenerated carriers in InGaN/GaN heterostructures observed by PL measurements

Abstract

In this paper we present a direct observation of the lateral diffusion of photogenerated carriers in InGaN/GaN quantum wells. The spatial distribution of the photoluminescence around a small exciting laser spot is analyzed by scanning in the focal plane of our confocal microscope. The results of a blue and a green emitting sample at varying excitation densities are discussed in the context of the theoretical model of the enhanced lateral diffusion. A lateral electric field which causes an additional radial drift motion was determined by analyzing the PL spectra and by solving a drift–diffusion equation for the lateral motion in the quantum well.