CHARACTERIZATION OF CUBIC CDS THIN-FILMS ANNEALED IN VACUUM

Cubic CdS thin films were grown on glass substrates by chemical bath d eposition and then thermally treated in the temperature range 180-430 degrees C at 10(-3) torr pressure of air atmosphere. From the [111] pe ak position in X-ray diffraction measurements, an increase in the latt ice parameter was found, and a reduction in the band-gap was also foun d by optical absorption measurements. Both result as a function of the thermal annealing. On the other hand, conductivity versus temperature data show that a large defect quantity, at intermediate temperatures (200-300 degrees C) of the above indicated range, was created. The var iable range hopping model of Mon was satisfied for these latter sample s, indicating a characteristic hopping conduction of carriers through deep levels. (C) 1998 Elsevier Science Ltd.