Effects of Annealing on Structural and Electrical Properties of CuInSe Thin Films Prepared by Hybrid Sputtering/Evaporation Processes.

CuInSe (CIS)-based absorber layers have been fabricated on soda-lime glass substrates by co-sputtering Cu/In and evaporating Se. The effects of annealing in the Se environment on the structural and electrical properties of the CIS layers were studied. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to investigate the surface morphology and crystal structures of the CIS films, respectively. XRD patterns showed that the CIS films had a single chalcopyrite structure with preferential (112) orientation. The asymmetry of the Se 3d x-ray photoelectron spectroscopy (XPS) peak for the as-grown films and a separated peak for the annealed films are indications of the existence of two different valence states in the two kinds of CIS films. The electrical properties of the CIS films were studied by the four-probe method and Hall measurements. The results showed that the as-grown films had lower carrier mobility than the annealed films. However, the as-grown films had higher carrier concentration. [ABSTRACT FROM AUTHOR]