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First Principles Study on Electronic Structure and Optical Properties of Ternary GaAs:Bi Alloy
School of Information Science and Engineering, Shandong University, Jinan 250100, China
* Author to whom correspondence should be addressed.
Received: 16 July 2012; in revised form: 20 August 2012 / Accepted: 21 November 2012 / Published: 26 November 2012
Abstract: The electronic structure and optical properties of ternary GaAs:Bi alloy are investigated by first principles calculations. It is found that the band gap of GaAs1-xBix decreases monotonously with the increasing of Bi concentration, resulting in the fundamental absorption edge and main absorption peaks of GaAs1-xBix shifting toward lower energy with the increase of the Bi content. The optical constants of GaAs1-xBix, such as the optical absorption coefficient, refractive index, extinction coefficient and optical conductivity, are greater than those of pure GaAs when x > 3.1%, but less than those of pure GaAs when x < 3.1%, which is primarily decided by the intraband level repulsions between Bi-induced states and host states on the valence bands; the contribution of Bi-6s, Bi-6p orbitals and Ga-4p, Ga-4s orbitals on conduction bands is also crucial. Bi doping plays an important role in the modulation of the static dielectric constant and the static refractive index. These results suggest a promising application of GaAs1-xBix alloy as a semiconductor saturable absorber.
Keywords: band structure; partial density of states; optical properties; first principles
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MDPI and ACS Style
Yu, L.; Li, D.; Zhao, S.; Li, G.; Yang, K. First Principles Study on Electronic Structure and Optical Properties of Ternary GaAs:Bi Alloy. Materials 2012, 5, 2486-2497.
Yu L, Li D, Zhao S, Li G, Yang K. First Principles Study on Electronic Structure and Optical Properties of Ternary GaAs:Bi Alloy. Materials. 2012; 5(12):2486-2497.
Yu, Lifei; Li, Dechun; Zhao, Shengzhi; Li, Guiqiu; Yang, Kejian. 2012. "First Principles Study on Electronic Structure and Optical Properties of Ternary GaAs:Bi Alloy." Materials 5, no. 12: 2486-2497.