Effect of a deep-level trap on hole transport in InAlAs/InGaAs metal-semiconductor-metal photodetectors

Summary form only given. InGaAs metal-semiconductor-metal (MSM) photodetectors with interdigital electrodes are promising for applications in high-speed fiber-optic and atmospheric communications. However, the existence of a long tail on the falling edge of the photoresponse slows the high-speed performance of MSMs. Initially, this long tail was believed to originate from slow hole transport due to charge accumulated at the abrupt heterojunction interface. Subsequently, graded InAlGaAs layers and InAlAs/InGaAs graded superlattices as transition layers were proposed to improve the hole transport to obtain high bandwidths. The influence of buffer layers and transition layers on device performance have been explored.