Photoluminescence efficiency of Al-rich AlGaN heterostructures in a wide range of photo-excitation density and temperatures

Abstract

Time-resolved photoluminescence and light-induced transient grating techniques were applied for the comparative investigation of the evolution of the internal quantum efficiency and of the carrier diffusion in AlxGa1-xN (x > 0.6) heterostructures in 80 – 550 K temperature range and for excitations from 1 µJcm-2 to 1 mJcm-2. The decrease of the photoluminescence efficiency measured at high excitations and temperatures is quantitatively correlated to the increase of the diffusion coefficients of carriers and to the increase of their non-radiative recombination rate on vacancies. Complex numerical modelling provides a full set of carrier and exciton recombination parameters.