The effect of postdeposition annealing on the structural and optoelectronic properties of copper bismuth selenide thin films by PVD

Copper bismuth selenide thin films were deposited on to the glass substrate by thermal evaporation method. The films were annealed at 200 A degrees C for various time duration (1, 2, 3 and 4 h) and studied the structural and opto-electrical physical properties of the films. Structural studies showed that the as-deposited film was amorphous in nature while crystalline peaks emerging in the annealed films and its intensity increase with the increase of annealing time. Crystallite size is found to be increased with increase in annealing duration which shows the enhance in crystallinity. All films shows optical absorption in the visible region and it increases for increase in annealing duration. The absorption coefficient is found to be about 10(4) cm(-1). The bandgap energy is found to be in the range of 1.99-1.67 eV. The electrical resistivity of the films was found in the range of 2.58 x 10(2) to 0.470 Omega m.