ZnO:Al thin films used in ZnO: Al/p-Si heterojunctions

Al-doped n-ZnO/p-Si heterojunctions were fabricated using a sol–gel dip coating technique at 700 °C, in a nitrogen ambient. The structural, optical, and electrical properties of ZnO:Al thin films, and the heterojunction properties of ZnO:Al/p-Si were investigated with respect to the effects of Al doping concentration. Hexagonal nano-structured ZnO: Al thin films with a 1.2% and a 1.6 at.% Al concentration exhibited high optical transmittance in visible ranges. Electrical resistivity changed with respect to Al doping concentration, and minimum resistivity was detected at a 1.2 at.% Al concentration. The ZnO:Al/p-Si heterojunction properties were analysed using current–voltage (I–V) measurements at four different Al concentrations, ranging from 0.8 to 1.6 (at.%). The ZnO:Al/p-Si heterojunctions exhibited diode-like rectifying behaviour. Under UV illumination, the photoelectric behaviour observed for the ZnO:Al/p-Si heterojunctions was diode.