Electrical characterization of <i>n</i>-amorphous/<i>p</i>-crystalline silicon heterojunctions

Abstract

n-type amorphous silicon on p-type crystalline silicon heterojunction diodes were fabricated and electrically characterized. The a-Si:H film was deposited by plasma enhanced chemical vapor deposition. Electrical properties were investigated by capacitance–voltage and current–voltage measurements at different temperatures. The capacitance–voltage results confirm an abrupt heterojunction. Current–voltage characteristics show good rectifying properties (50000:1 at ±0.5 V). A detailed analysis of transport mechanisms was developed in order to establish a unified model of conduction. Two carrier transport mechanisms are believed to be at the origin of the forward current. At low bias voltage (V&amp;lt;0.4 V), the current is determined by recombination at the amorphous side of the space charge region, while at higher voltages (V≳0.6 V), the current becomes space charge limited.