Annealing effect on optical and electronic properties of silicon rich amorphous silicon-carbide films

doi:10.1007/s12200-012-0196-7

Front Optoelec

2012, Vol. 5

Issue (1) : 107-111 https://doi.org/10.1007/s12200-012-0196-7

RESEARCH ARTICLE

Annealing effect on optical and electronic properties of silicon rich amorphous silicon-carbide films

Shuxin LI¹, Yunjun RUI^1,2, Yunqing CAO¹, Jun XU¹(

), Kunji CHEN¹

1. Nanjing National Laboratory of Microstructures, School of Electronic Science and Engineering, School of Physics, Nanjing University, Nanjing 210093, China; 2. Department of Applied Physics, Nanjing University of Technology, Nanjing 210009, China

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Abstract

A series of Si-rich amorphous silicon carbide (a-SiC:H) thin films were deposited in conventional plasma enhanced chemical vapor deposition system with various gas ratio R = [CH₄]/[SiH₄]. The microstructural, optical and electronic properties of as-deposited films were investigated in this study. It was found that optical band gap was linearly proportional to carbon content in the films and it could be controlled in a range of 1.8–2.4 eV by changing the gas ratio, R. Both dark and photo conductivities in room temperature were decreased with the increasing of carbon content in the films, and the photosensitivity reached as high as 10⁴ for the film with the optical band gap of 1.96 eV. The as-deposited samples were subsequently annealed at the temperatures of 900°C and 1000°C. The formation of nanocrystalline silicon (nc-Si) dots in amorphous silicon carbide (a-SiC) host matrix was shown. The dark conductivity was enhanced by five orders of magnitude after annealing compared with that of as-deposited films. The result of temperature-dependent conductivity suggested that the property of carrier transport was dominated by conduction process between the extended states. Furthermore, room temperature electroluminescence (EL) was achieved from nc-Si/SiC system and the possible mechanism of radiative recombination mechanism was discussed.

Keywords amorphous silicon carbide (a-SiC) optical band gap photo-conductivity dark conductivity electroluminescence (EL)

Corresponding Author(s): XU Jun,Email:junxu@nju.edu.cn

Issue Date: 05 March 2012

Cite this article:

Shuxin LI,Yunjun RUI,Yunqing CAO, et al. Annealing effect on optical and electronic properties of silicon rich amorphous silicon-carbide films[J]. Front Optoelec, 2012, 5(1): 107-111.

URL:

https://academic.hep.com.cn/foe/EN/10.1007/s12200-012-0196-7
https://academic.hep.com.cn/foe/EN/Y2012/V5/I1/107

Fig.1 Optical band gap as a function of the carbon content for as-deposited a-SiC:H films

Fig.2 Absorption coefficient spectra of as-deposited a-SiC:H films

Fig.3 Dark and photo-conductivity of as-deposited a-SiC:H films measured at room temperature

Fig.4 Raman spectra of the sample with carbon content = 0.27 before and after annealing at 900°C and 1000°C

Fig.5 Temperature-dependent dark conductivity of the as-deposited, 900°C and 1000°C annealed sample with the carbon content = 0.27

Fig.6 (a) Room temperature EL spectra of the sample with the carbon content = 0.27 after annealing at 900°C and 1000°C measured at the same injection current ( = 44 mA); (b) EL spectra of 900°C annealed a-SiC film and 900°C annealed a-SiC film

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