Effect of Al doping on structural, morphological, optical, and electrical properties of Cu2ZnSnS4 thin films prepared by sol-gel spin coating

Preparation of aluminum (Al) -free and Al- doped copper zinc tin sulfide (CZTS) thin films have been reported using low-cost, low-temperature (280 °C) sol-gel spin coating method without sulfurization. Effect of Al doping on structural, morphological, optical and electrical properties of the films have been presented. It has been found that both Al-free CZTS thin film sample (S0) and Al-doped CZTS thin film samples with 1% (S1), 3% (S2) and 4% (S3) show kestrite, polycrystalline tetragonal structure using X-ray diffraction and confirmed with Raman spectroscopy measurements. Scanning electron microscope (SEM) images show that the undoped sample has 3D architecture structure with porous flake-like surface, while the doped samples are smooth and with less porous structure. Energy dispersive spectroscopy results have been presented for reporting chemical composition of the constituting elements. Effect of …