Structural and optical properties of CdGa2Se4thin films

✍ Scribed by H. S. Soliman; T. Hindia; H. Abo Dorra; E. Hashem

• Publisher: Springer US
• Year: 1994
• Tongue: English
• Weight: 401 KB
• Volume: 5
• Category: Article
• ISSN: 0957-4522
• DOI: 10.1007/bf00186195

✦ Synopsis

CdGa2Se 4 thin films were prepared by vapour deposition onto either room temperature or preheated quartz and glass substrates (Ts) or they were deposited at room temperature and then annealed at about (TA) 623 K. The films thus prepared were crystalline with a thiogallate tetragonal structure. The optical constants (the refractive index n and the absorption index, k) were determined for CdGa2Se 4 films deposited onto quartz substrates held at either room temperature or at T s = 573 K. These constants were also determined for preannealed films (TA = 623 K). Plots of (=hv) 2 = f(hv) and (0~hv) 1/2 = g(hv) were linear, indicating the existence of both direct and indirect optical transitions. It was found that the values of E d and E~ nd for as-deposited CdGa2Se4 films were 2.46 and 1.91 eV, respectively. The corresponding values for the annealed films and the films deposited at Ts = 573 K were 2.56 and 2.06 eV, respectively.