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

The photovoltage (PV) response of single quantum well p-i-n structures unde r open circuit conditions has been studied experimentally and numerically. The numerical calculations show a monotonic increase in the PV response wit h decreasing well width, implying that the ensuing increase in carrier gene ration rate and band gap governs the PV response. The well layer has been s hown to dominate the recombination of excess carriers generated throughout the structure, and their lifetime at the well has been found to be a critic al structure parameter. Using a simple semi-empirical model, the effective carrier lifetimes at the well layer/interfaces for the different samples we re estimated. The results demonstrate the benefits of using surface photovo ltage spectroscopy for characterization and quality control of quantum well structures. (C) 1999 American Institute of Physics. [S0021-8979(99)04724-6 ].