ABSTRACT
The anomalous current-voltage characteristics of strain-balanced multi-quantum well (SBMQW) solar cells grown on InP, were correlated with the electrical properties of extended defects generated by the local breakdown of the highly strained sequence of lnGaAs layers. The analysis of electron beam induced current (EBIC) images reveals that the charge collection efficiency is enhanced at the boundaries of the extended defects when carriers are generated in the depletion region. The bright EBIC contrast is found to be due to the local partial compensation of a notch in the valence band at the hetero interface between the p and the i regions. InP based p-i-n photovoltaic cells containing a SBMQW in the intrinsic region are used for thermophotovoltaic applications where the highly efficient photovoltaic conversion of near-infrared radiation is required. The MQW thickness modulations always start in the tensile barrier layers and propagate vertically with increasing amplitude through the MQW structure.
