Photovoltaic characteristic of Al-doped ZnO/Si heterojunction

A heterojunction composed of n-type Al-doped ZnO and p-type Si was fabricated and its photovoltaic properties were studied at room temperature. The heterojunction exhibits an asymmetric current–voltage relation with good rectifying characteristic. Clear photovoltaic signals are observed when the heterojunction is irradiated by the laser pulses of 308, 532 and 1064 nm, and the voltage responsivity of the 308 nm irradiation is lower than that for 532 and 1064 nm irradiations. The mechanism is proposed based on the band structure of the p–n heterojunctions. The results suggest that this Al-doped ZnO/Si heterojunction has a great potential application in the wide-band photodetectors from ultraviolet to near infrared.