Schottky barrier characteristics and internal gain mechanism of TiO2 UV detectors

Haifeng Zhang; Min Zhang; Caihui Feng; Weiyou Chen; Caixia Liu; Jingran Zhou; Shengping Ruan

doi:10.1364/AO.51.000894

Schottky barrier characteristics and internal gain mechanism of TiO2 UV detectors

Appl Opt. 2012 Mar 1;51(7):894-7. doi: 10.1364/AO.51.000894.

Authors

Haifeng Zhang¹, Min Zhang, Caihui Feng, Weiyou Chen, Caixia Liu, Jingran Zhou, Shengping Ruan

Affiliation

¹ State Key Laboratory on Integrated Optoelectronics, Jilin University, 2699 Qianjin Street, Changchun 130012, China. wolfzhang2007@163.com

PMID: 22410892
DOI: 10.1364/AO.51.000894

Abstract

High-responsivity metal-semiconductor-metal TiO(2) UV photodetectors with Ni and Au electrodes were fabricated identically. Their Schottky barrier heights and photocurrent gain mechanism were studied. The effective barrier height Φ and ideality factor n were evaluated according to the thermionic emission theory. The result that Φ(Ni) was lower than Φ(Au) may be attributed to the electron transfer from Ni to the TiO(2) substrate, which would lead to a dipole layer and, accordingly, decrease the barrier height. In addition, the I-V characteristics of the Ni/TiO(2)/Ni and Au/TiO(2)/Au photodetectors were observed. A significant internal gain was obtained, and the mechanism of the internal gain was studied by the phototransistor model in detail.