Control of Grain in Cu(In,Ga)Se₂Thin Films Prepared by Selenization Method Using Diethylselenide

Abstract

The relationship between the selenization condition and the grain structure has been studied. A single-phase chalcopyrite Cu(In,Ga)Se2 thin film with densely-packed grains and large grains have been prepared by the two-step selenization of the In/Cu–Ga bilayer precursor using diethylselenide (DESe). The formation of the In–Se compound in the early stage of the first-step selenization (T=350–450 °C) has been found to be important. The succeeding second-step selenization at high temperature of 540 °C led to the well developed (112) grain formation. The relationship between the selenization condition and the CIGS film structure is discussed with relation to the selenization mechanism.