Tuning to the band gap by complex defects engineering: insights from hybrid functional calculations in CuInS2. (14th December 2017)

• Record Type: Journal Article
• Authors: Yang, Pei; Shi, Li-Jie; Zhang, Jian-Min; Liu, Gui-Bin; Yang, Shengyuan A; Guo, Wei; Yao, Yugui
• Is Part Of: Journal of physics. Volume 51:Number 2(2018)
• Publication Date: 2017-12-14
• Subjects: CuInS2 -- first principles -- complex defect -- formation energy -- Cu/In molar ratio -- band gap tuning; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/aa9c17
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Tuning band gaps of semiconductors in terms of defect control is essential for the optical and electronic properties of photon emission or photon harvesting devices. By using first-principles calculations, we study the stability condition of bulk CuInS2 and formation energies of point and complex defects in CuInS2 with hybrid exchange-correlation functionals. We find that at Cu-rich and In-poor conditions, 2Cui + CuIn is the main complex defect, while InCu + 2VCu is the main complex defect at In-rich and Cu-poor conditions. Such stable complex defects provide the feasibility of tuning band gaps by varying the [Cu]/[In] molar ratios. These results present how the off-stoichiometry CuInS2 crystal structures, and electronic and optical properties can be optimized by tuning the [Cu]/[In] ratio and Fermi level, and highlight the importance of complex defects in achieving better photoelectric performance in CuInS2 . Such band gap tuning in terms of complex defect engineering is a general approach and thus applicable to other photo-harvest or light-emission semiconductors.