The effect of high growth temperature on Cu(In,Ga)Se2 thin film solar cells

• High Cu(In,Ga)Se2 growth temperature increases grain size.
• Higher growth temperature flattens the [Ga]/([Ga]+[In]) gradient.
• A higher Ga interfusion demands modifications to the growth process.
• Solar cells prepared at higher temperature have similar efficiency as reference ones.

The morphological, elemental distribution and electrical performance effects of increasing the Cu(In,Ga)Se2 (CIGS) growth substrate temperature are studied. While the increased substrate growth temperature with no other modifications led to increased CIGS grain size, it also resulted in depth profile flattening of the [Ga]/([Ga]+[In]) ratio. Tuning the Ga profile in the high temperature process led to a more desirable [Ga]/([Ga]+[In]) depth profile and allowed a comparison between high and standard temperature. Devices prepared at higher temperature showed an improved grain size and the electrical performance is very similar to that of the reference sample prepared at a standard temperature.