A p-i-n thermo-photovoltaic diode

The analysis, fabrication, and operation of a p-in photovoltaic cell that is suitable for use at the very high illumination intensities, which are encountered in a thermo-photovoltaic system, are presented. The device performance has been measured under pulse conditions to 790 W/cm²of incident radiation. The efficiency of operation is limited at very high illumination levels by an increase in the reflection coefficient. Open circuit voltages of 0.42 volts and short circuit currents in excess of 40 A/cm²of illuminated surface have been observed for germanium devices. Operating efficiencies at various incident light intensities are reported. The analysis includes an estimate of the effect of the electric field that occurs in the intrinsic region.