Growth and characterization of co-evaporated Cu2ZnSnSe4 thin films for photovoltaic applications

• Published in: Journal of physics. D, Applied physics Applied physics, 2008-10, Vol.41 (20), p.205305-205305 (7)
• Main Authors: Suresh Babu, G, Kishore Kumar, Y B, Uday Bhaskar, P, Sundara Raja, V
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Other inorganic semiconductors; Other semiconductors; Physics
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/41/20/205305

Cu2ZnSnSe4 thin films are deposited using the four-source co-evaporation technique onto glass substrates held at 523, 573, 623 and 673 K and in situ annealed at 723 K for 1 h in a selenium atmosphere. XRD studies revealed that the films deposited at 523 and 573 K and annealed at 723 K contain ZnSe as a secondary phase. However, films deposited at 673 K and annealed at 723 K have Cu2-xSe as a secondary phase along with Cu2ZnSnSe4. Single phase, polycrystalline Cu2ZnSnSe4 films are obtained at a substrate temperature (Ts) of 623 K on in situ annealing at 723 K. The structure is found to be kesterite and the lattice parameters are a = 0.569 nm, c = 1.141 nm. The direct optical band gap of the films is found to lie between 1.42 and 1.57 eV for films deposited at different substrate temperatures. Electrical resistivity of the films is in the range 0.1-0.8 Omega cm depending on Ts.