First-principles investigation on the vacancy dependence on the optical and electronic properties of Bi2S3 semiconductor ceramics

Although Bi2S3 is prospective as the semiconductor ceramics, the effects of vacancy on the structural, optical and electronic properties are not clarified. In present work, the first-principles calculations were adopted to study the structural stability, optical and electronic properties of Bi2S3 with five kinds of vacancies. The five vacancy models possess the structural stability by comparing the values of vacancy formation energy. The optical properties of Bi2S3 respond to the ultraviolet light region. And Bi2S3 with V-(S3) vacancy increases the absorption coefficient of original Bi2S3. The calculated values of band gap indicate that Bi2S3 and Bi2S3 with different vacancies are all semiconductor materials. All considered vacancies narrow the band gap of original Bi2S3 and make more electron transition become possible.