GaAs/AIGaAs single quantum well p-i-n structures: A surface photovoltage study

The photovoltage (PV) response of single quantum well p-i-n structures under open circuit conditions has been studied experimentally and numerically. The numerical calculations show a monotonie increase in the PV response with decreasing well width, implying that the ensuing increase in carrier generation rate and band gap governs the PV response. The well layer has been shown to dominate the recombination of excess carriers generated throughout the structure, and their lifetime at the well has been found to be a critical structure parameter. Using a simple semi-empirical model, the effective carrier lifetimes at the well layer/interfaces for the different samples were estimated. The results demonstrate the benefits of using surface photovoltage spectroscopy for characterization and quality control of quantum well structures.