Characterization of porous silicon photovoltaic devices through rapid thermal oxidation, rapid thermal annealing and HF-dipping processes

Abstract

The characteristics of a porous silicon Schottky barrier are improved through rapid thermal oxidation and rapid thermal annealing processes. However, the photovoltaic photocurrent at zero bias is degraded seriously by the thin oxide formed under the metal contact after the rapid thermal oxidation and the rapid thermal annealing processes. An HF-dipping process is used to remove the oxide of the metal contact area and to improve the short-circuit current and the open-circuit voltage. Under the optimum preparation conditions, a short-circuit current of about 4 mA and an open-circuit voltage of about 0.52 V are obtained under a tungsten lamp illumination of 22.4 mW/cm 2. The main problem is the series resistance of the high-resistivity substrate, the photovoltaic characteristics can be further improved if a low-resistivity substrate is used.