Temperature-dependent rectifying and photovoltaic characteristics of an oxygen-deficient Bi₂Sr₂Co₂O_y/Si heterojunction

A Bi₂Sr₂Co₂O_y/Si heterojunction is obtained by growing a layer of p-type oxygen-deficient Bi₂Sr₂Co₂O_y film on a commercial n-type silicon wafer by pulsed laser deposition. Its rectifying and photovoltaic properties are studied in a wide temperature range from 20 K to 300 K. The transport mechanism under the forward bias can be attributed to a trap-filled space-charge-limited current conduction mechanism. Under the irradiation of a 532-nm continuous wave laser, a clear photovoltaic effect is observed and the magnitude of photovoltage increases as the temperature decreases. The results demonstrate the potential application of a Bi₂Sr₂Co₂O_y-based heterojunction in the photoelectronic devices.