Photoresponse of SnO2 nanobelts grown in situ on interdigital electrodes

The photoresponses of SnO2 nanobelts grown in situ among interdigital electrodes on silicon substrates were investigated under ultraviolet (UV) light and green laser illumination. The current increased to similar to 140 nA in vacuum under green laser irradiation with a power of 35.1 mW. Under UV illumination, however, the source-drain current increased to similar to 80 mu A in air and up to similar to 900 mu A in vacuum, respectively. The UV photoresponse was a result of electron transition from the valence band to the conduction band, while the green laser photoresponse was dependent on oxygen pressure, ambient temperature and defect levels.