Crystal structure and elementary electronic properties of Bi-stabilized ¦Á-In₂Se₃

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• 作者：Huiwen Ji^a ; ^{huiwenji@princeton.edu} ; Anjan Reijnders^b ; Tian Liang^c ; L.M. Schoop^a ; K.S. Burch^b ; ^d ; N.P. Ong^c ; R.J. Cava^a
• 关键词：A. Chalcogenides ; A. Optical materials ; C. X-ray diffraction ; D. Electrical properties ; D. Optical properties
• 刊名：Materials Research Bulletin
• 出版年：2013
• 出版时间：July, 2013
• 年：2013
• 卷：48
• 期：7
• 页码：2517-2521
• 全文大小：1105 K

文摘

The introduction of Bi as a substitution for In at ~12 % in In₂Se₃ stabilizes the ¦Á-polymorph and facilitates the crystal growth by the modified Bridgeman method. The crystal structure (R?3m, Z = 3, a = 3.9978(8) ?, c = 28.276(6) ?) and composition, (In_0.88Bi_0.12)₂Se₃, of the crystals were determined by single crystal X-ray diffraction. The structure, of the tetradymite type, displays positional disorder within the middle Se layer. Optical measurements indicate that (In_0.88Bi_0.12)₂Se₃ has an indirect band gap of about 1.19 eV, shown by electronic structure calculations to be from valence band states near the ¦£ point to conduction band states at the L point. Resistivity and Hall effect measurements on Sn-doped crystals of composition (In_0.88Bi_0.115Sn_0.005)₂Se₃ show it to have a relatively high semiconducting resistivity, about 6 ¡Á 10⁴ ¦¸ cm at 300 K, with an n-type carrier concentration varying from 10¹²/cm³ at 300 K to 10¹⁵/cm³ at 400 K.