Structures and optical absorption of Bi2OS2 and LaOBiS2. (February 2016)

• Record Type: Journal Article
• Authors: Miura, Akira; Mizuguchi, Yoshikazu; Takei, Takahiro; Kumada, Nobuhiro; Magome, Eisuke; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Tadanaga, Kiyoharu
• Is Part Of: Solid state communications. Volume 227(2016)
• Page Start: 19
• Page End: 22
• Publication Date: 2016-02
• Subjects: Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2015.11.016
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: The band gaps of isostructural Bi2 OS2 and LaOBiS2 were examined using optical absorption and discussed with the band structures calculated based on the crystal structures determined using synchrotron X-ray diffraction. The Bi 6p and S 3p orbitals in the Bi–S plane were computationally predicted to constitute the bands near the Fermi level. The optical reflectance spectra of Bi2 OS2 and LaOBiS2 showed optical band gaps of ~1.0 eV, which were close to the computationally calculated direct band gaps of ~0.8 eV. Our results show that Bi2 OS2 and LaOBiS2 are semiconductors containing direct band gaps of 0.8–1.0 eV, and they are suggested to be candidates for optoelectronic materials in the near-infrared region without highly toxic elements. Highlights: Crystal structures of Bi2 OS2 and LaOBiS2 were proposed. Bi2 OS2 and LaOBiS2 were calculated to have direct band gaps of ~0.8 eV. Optical absorption of Bi2 OS2 and LaOBiS2 showed band gaps of ~1.0 eV.