Effect of the growth temperature on the structural, morphological and electrical properties of CuIn0.7Ga0.3Se2 layers grown by CSVT technique

Layers of CuIn0.7Ga0.3Se2 have been prepared by a CSVT technique on which improvements have been brought, permitting a better control of the growth conditions and reducing the cost of the installation. The effect of the substrate temperature on the composition of the layers and on their structural, morphological and electrical properties is discussed. The X-ray analysis shows that the crystalline state of the layers depends on the substrate temperature and especially on the gradient of temperature between the substrate and the source. A preferential (112) orientation and a more pronounced columnar structure are observed for the higher source-substrate gradient temperature. Electrical resistivity shows a change of two orders of magnitude, from 0.29 to 25.1 Ω cm, when the substrate temperature varies from 405 °C to 460 °C. Mott type variable range hopping conduction between 77 and 200 K is observed for samples grown at substrate temperatures higher than 405 °C.