Selenisation of sequentially electrodeposited Cu–Zn and Sn precursor layers

Cu2ZnSnSe4 (CZTSe) thin films were produced through the selenisation of sequentially electrodeposited Cu–Zn and Sn stacked films. The micro-structural and compositional properties of the precursor stacked and selenised films were characterised using scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction and Raman spectroscopy. The electrodeposited Cu–Zn layers had a high concentration of zinc to compensate for the loss of zinc that occurred during the following deposition of the tin layer. It was observed that a Cu/Zn ratio equal to 1.1 in the electrodeposited Cu–Zn layers is optimal and provides the desired ratio of all the metallic components in selenised CZTSe films. Selenisation for 60 min resulted in highly crystalline CZTSe films with a grain size of 1.5–4 μm. In addition, the influence of the Cu–Zn ratio in the electrodeposited stacked layers on the morphology and the elemental and phase compositions of the CZTSe films was investigated.

► Electrodeposition-annealing route is used to form Cu2ZnSnSe4 (CZTSe) absorber films
► Two series of precursors with different Cu–Zn ratio are prepared and selenised.
► CZTSe absorber layer containing large grains (1.5–4 μm) is formed after annealing.
► Morphological and compositional properties of formed CZTSe films are studied.