Optoelectronic characterization of CuInGa(S)${}_2$ thin films grown by spray pyrolysis for photovoltaic application

Copper–indium gallium disulfide (CIGS) is a good absorber for photovoltaic application. Thin films of CIGS were prepared by spray pyrolysis on glass substrates in the ambient atmosphere. The films were characterized by different techniques, such as structural, morphological, optical and electrical properties of CIGS films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), spectrophotometer and Hall effect, respectively. After optimization, the deposited films structure, grain size, and crystallinity became more important with an increase of annealing time at 370 °C for 20 min. Transmission electron microscopy (TEM) analysis shows that the interface sheets are well crystallized and the inter planer distance are 0.25 nm, 0.28 nm, and 0.36 nm. The atomic force microscopy (AFM) observation shows that the grain size and roughness can be tolerated by optimizing the annealing time. The strong absorbance and low transmittance were observed for the prepared films with a suitable energy bandgap about 1.46 eV. The Hall effect measurement system examined that CIGS films exhibited optimal electrical properties, resistivity, carrier mobility, and carrier concentration which were determined to be 4.22 × 10${}^6$ Ω cm, 6.18 × 10${}^2$ cm${}^2$ V${}^{-1}$ S${}^{-1}$ and 4.22 × 10${}^6$ cm${}^{-3}$, respectively. The optoelectronic properties of CIGS material recommended being used for the photovoltaic application.