Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5350140 | Applied Surface Science | 2017 | 7 Pages |
Abstract
In this work, we investigate the broad-band photoabsorption of an n-TiO2 thin film and its hole-blocking properties when a heterostructure is grown on a chemically textured p-Si substrate. We demonstrate that average specular reflectance of conformally grown TiO2 thin films on chemically prepared pyramidally textured Si substrates can be brought down to â¼0.2% (in the wavelength range of 300-1200Â nm), which increases up to â¼0.53% after annealing at 673Â K in air for 1Â h. X-ray diffraction data reveal the amorphous nature of as-grown TiO2 thin films which undergoes a transition to a crystalline one after annealing. In addition, bulk current-voltage characteristics show that the leakage current increases after annealing which corroborates well a with change in the band gap, as is measured from the optical absorption spectra, due to a transition from amorphous to crystalline (anatase phase) of TiO2. Moreover, TiO2/Si heterojunction allows the transport of electrons but blocks the transport of holes. The present results are not only important for the fundamental understanding of the charge transport across TiO2/Si heterostructures but also to design hole-blocking solar cells.
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Authors
Ranveer Singh, Mohit Kumar, Mahesh Saini, Avanendra Singh, Biswarup Satpati, Tapobrata Som,