Abstract
A novel silane coupling agent grafting TiO(2)nanorod arrays (C3H8NSi-TiO2NRAs)/n-Si heterojunction is introduced. A built-out electric field is created on the surface of TiO2NRAs by silane coupling agent modifications, which can promote photo-generated carriers separation so that the C3H8NSi-TiO2NRAs/n-Si heterojunction shows excellent self-powered broadband photoresponse properties. Especially under 900 nm illumination, the self-powered device demonstrates the responsivity (R), detectivity (D*), and sensitivity (S) of approximate to 7.76 A W-1, approximate to 5.22 x 10(14)Jones, and approximate to 1.12 x 10(10)cm(2)W(-1), respectively. Compared with that of the unmodified TiO2NRAs/n-Si heterojunction, theR,D*, andSare increased by two orders of magnitude. The results are mainly ascribed to the original built-in electric field of heterojunction and the created built-out electric field which jointly promote carriers separation and the unconventional porous electrode which plays a crucial role in collecting holes. The DFT calculations and TRPL results indicate the formation and carriers separation capability of the built-out electric field. This design concept can be extended to the application of other varieties of metal oxide based photoelectric devices.