Recrystallization of Cu(In,Ga)Se2 Semiconductor Thin Films via InCl3 Treatment

One of the key challenges to promote the economic viability of Cu(In,Ga)Se2 (CIGS) solar cells is the multi-stage co-evaporation process required to make a high quality absorber layer. One phenomenon of interest is dynamic recrystallization using a fluxing agent. While these techniques have significantly improved material systems like CdTe, their impact on other nonmetallic systems are relatively unexplored. In this paper, we demonstrate that InCl3 can be used effectively to recrystallize CIGS for temperature as low as 450°C, but that it also induces a modification of the surface composition. Analyses, notably via glancing incidence X-ray diffraction and secondary ion mass spectrometry, show an indium enriched surface as well as a modified alkali profile.