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 ∼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 ∼80 μA in air and up to ∼900 μA 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.