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Great Enhancement of Self‐Powered Photoresponse Performance of C 3 H 8 NSi‐TiO 2 NRAs/n‐Si Heterojunction by Build‐In and Build‐Out Electric Field Jointly Promoting Carrier Separation
Author(s) -
Hou Zhidong,
Li Guixia,
Ling Cuicui,
Wang Hongyan,
Zhu Lei,
Guo Tianchao,
Zhang Tuo,
Feng Bingxin,
Cao Min,
Xue Qingzhong
Publication year - 2020
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202000501
Subject(s) - heterojunction , materials science , electric field , responsivity , nanorod , optoelectronics , photoelectric effect , nanotechnology , photodetector , physics , quantum mechanics
A novel silane coupling agent grafting TiO 2 nanorod arrays (C 3 H 8 NSi‐TiO 2 NRAs)/n‐Si heterojunction is introduced. A built‐out electric field is created on the surface of TiO 2 NRAs by silane coupling agent modifications, which can promote photo‐generated carriers separation so that the C 3 H 8 NSi‐TiO 2 NRAs/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 ≈7.76 A W −1 , ≈5.22 × 10 14 Jones, and ≈1.12 × 10 10 cm 2 W −1 , respectively. Compared with that of the unmodified TiO 2 NRAs/n‐Si heterojunction, the R , D* , and S are 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.