Structural and electrical properties of CuGaS2 thin films by electron beam evaporation

Single phase CuGaS2 thin film with a highest diffraction peak of (1 1 2) at a diffraction angle (2θ) of 28.8° was made at a substrate temperature of 70°C, an annealing temperature of 350°C and an annealing time of 60 min. Second highest (2 0 4) peak was shown at diffraction angle of (2θ) 49.1°. Lattice constant of a and c of that CuGaS2 thin film was 5.37 and 10.54 Å, respectively. The greatest grain size of the thin film was about 1 μm. The (1 1 2) peak of single phase of CuGaS2 thin film at an annealing temperature of 350°C with excess S supply appeared at a little higher about 10% than that of no excess S supply. The resistivity, mobility and hole density at room temperature of p-type CuGaS2 thin film was 1.4 Ω cm, 15 cm2/V s and 2.9×1017 cm−3, respectively. It was known that carrier concentration had considerable effect than mobility on a variety of resistivity of the fabricated CuGaS2 thin film, and the polycrystalline CuGaS2 thin films were made at these conditions were all p-type.