Demonstration and control of the fast absorption recovery times of the InGaN/GaN quantum well saturable absorbers

InGaN/GaN multiple quantum well samples were grown by metal organic chemical vapor deposition with thinner low-temperature GaN buffers than that in the conventional structure. It was found that the absorption recovery times of the InGaN/GaN quantum wells can be controlled by varying the thickness of the low-temperature GaN buffers. Transmission electron microscopy results showed that increased dislocations were introduced in the quantum well region with decreased low-temperature GaN buffer thickness. The degraded crystalline quality of the absorbing regions caused an increased density of nonradiative recombination centers, which were responsible for the fast recovery of the absorption.