Optical properties of nitride semiconductors: quantitative analysis of radiative and non-radiative recombination processes

Abstract

Nitride semiconductors are used in the active layers of LEDs and lasers with various emission colors. However, problems of decreasing emission efficiency occur at longer wavelengths and with increasing current; furthermore, the mechanisms of radiative and non-radiative recombination processes that govern these phenomena require to be understood. Therefore, the internal quantum efficiency (the ratio of the number of radiatively-recombined carriers to the total number of recombined carriers) must be accurately measured, but doing so is difficult. Furthermore, the measurement method is still being debated. In this paper, we introduce recent progress on the mechanisms of radiative and non-radiative recombination processes in nitride semiconductors and on methods for measuring the internal quantum efficiency.