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• InCl 3 used to recrystallize Cu(In,Ga)Se 2 films at low temperature. • Large grains are obtained for temperature as low as 450 °C. • The films become overall indium rich with an indium rich surface. • The alkali profile is modified. One of the key challenges to promote the economic viability of Cu(In,Ga)Se 2 (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 InCl 3 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. [ABSTRACT FROM AUTHOR]

Cu(In,Ga)Se2 (or CIGS) thin films and devices were fabricated using a modified three-stage process. Using high deposition rates and a low temperature during the process, a copper chloride vapor treatment was introduced in between the second and third stages to enhance the films properties. X-ray diffraction and scanning electron microscopy demonstrate that drastic changes occur after this recrystallization process, yielding films with much larger grains. Secondary ion mass spectrometry shows that the depth profile of many elements is not modified (such as Cu, In and Se) while others change dramatically (such as Ga and Na). Because of the competing effects of these changes, not all parameters of the solar cells are enhanced, yielding an increase of 15% in the device efficiency at the most. [ABSTRACT FROM AUTHOR]

• In-situ AgBr treatment used to deposit homogeneous CuGaSe 2 material. • CuGaSe 2 deposition time reduced by nearly half. • Higher and more consistent open-circuit voltage and fill factor for devices. Homogeneous CuGaSe 2 thin film growth is limited by slow kinetics of formation. A modified growth process was previously developed to address this issue but requires two separate long, high temperature anneals. Here, we demonstrate that a short AgBr treatment can replace this modified growth process. The AgBr works as a transport agent to catalyze CuGaSe 2 formation and atomic mobility. This treatment results in large grains with homogeneous composition through the bulk. Solar cells made with this material show better performance. [ABSTRACT FROM AUTHOR]