Effect of Substrate Temperature on Preferred Orientation and Ga Composition Profile of Co-Evaporated Cu(In,Ga)Se 2.

Cu(In,Ga)Se2(CIGS) films were deposited by the three-stage co-evaporation process and the effect of the second stage substrate temperature on device performance were evaluated. With increasing the substrate temperature, the preferred orientation of CIGS was found to be changed from (112) to (220), however, the Ga double grading became weaker and nearly flat for the (220) textured CIGS grown at 570°C. Despite of (220) preferred orientation, the conversion efficiency decreased mainly due to the poor fill factor and open circuit voltage. It is suggested that increasing the growth temperature in order to get (220) preferred CIGS may destroy the advantage of double-graded Ga profile. [ABSTRACT FROM AUTHOR]