Influence of N2 doping on photodective properties of p-typed Zn-N co-doped SnO2/n-Si heterojunction

Abstract

This work studied the effects of Zn and N co-doping on the crystal structure, electrical properties, and photoelectric effects of p-typed Zn-N co-doped SnO2/n-Si heterojunction. Zn and N co-doped SnO2 films (ZNTO) were deposited on n-type Si substrates at 300oC in different sputtering gas mixture Ar/N2 (% N = 0%, 30%, 50%, 60%, 70 % and 80%) from 5 wt% ZnO doped SnO2 target by the DC magnetron sputtering method. The crystal structure, surface morphology, chemical composition, electrical properties, and photoelectric effects of ZNTO films were investigated by measurements such as X-ray diffraction, FESEM, AFM, EDS, Hall, and I-V. The results showed that all films had a rutile structure, and the SnO2 (101) reflection was dominant on the optimal fabrication of 70% N2. Substitution of Sn4+ by Zn2+ and O2􀀀 by N3􀀀 were determined by the X-ray diffraction pattern (XRD) and X-ray energy scattering spectrum (EDS). The lowest resistivity for the ZNTO-5-70 film was r= 6.5010􀀀2 W.cmwith carrier concentration n = 1.461019 cm􀀀3 and hole mobility m = 6.52 cm2.V􀀀1.s􀀀1 respectively. I-V characteristics of the p – ZNTO – 5 – y/n – Si under the illumination condition showed the p-type electrical properties and their application as optical sensors. The ZNTO – 5 – y films' optical response current characteristic had high sensitivity and good reproducibility.