Effect of vacuum annealing temperature on structural, morphological and optical properties of In2S3:Zn films deposited by spray pyrolysis

• DOI: 10.1007/s10854-016-4959-6
• Publication Date: 2016-05-17T11:00:18Z
• Authors: J. Koaib; N. Bouguila; M. Kraini; A. Mhamdi; I. Halidou; M. Ben Salem; H. Bouzouita; S. Alaya
• Keywords: Tetragonal crystal system; Spray pyrolysis

Zinc-doped In2S3 thin films have been deposited by spray pyrolysis method at 350 °C on glass substrates with ITO contacts. The samples were sealed under vacuum (10−3 Torr) into a Pyrex tube and then annealed for 2 h at temperatures ranging from 300 to 450 °C with a step of 50 °C. The effect of the annealing temperature (Ta) on structural, morphological and optical properties of the In2S3 films was studied. The films, annealed at Ta ≤ 300 °C, result in films that consist of tetragonal β-In2S3 phase with (220) preferential orientation, while for films annealed at Ta > 300 °C, a structural transition from tetragonal to cubic β-In2S3 occurs with (400) preferential orientation. The film grain size decreases from 42 to 33 nm. The surface morphology analysis reveals that the films annealed at 300 °C present an average roughness of 40 nm. The optical band gap is found to be direct and it decreases with the increase of annealing temperature. A higher optical transmittance of 80 % is obtained at Ta = 350 °C.