Chemically Deposited Silver Antimony Selenide Thin Films for Photovoltaic Applications

Abstract

Silver antimony selenide (AgSbSe₂) thin films were prepared by heating sequentially deposited antimony sulphide (Sb₂S₃), silver selenide (Ag₂Se) and Ag thin films in close contact with a selenium thin film. Sb₂S₃ thin film was prepared from chemical bath containing SbCl₃ and Na₂S₂O₃, Ag₂Se from the bath containing AgNO₃ and Na₂SeSO₃ and Se thin films from an acidified solution of Na₂SeSO₃, at room temperature on cleaned glass substrates. Ag thin film was deposited by vacuum thermal evaporation. The annealing temperature was varied from 300-390°C in vacuum (∼10⁻³ Torr) for 1 h. X-ray diffraction analysis showed the films formed at 350 °C was polycrystalline AgSb(S,Se)₂ or AgSbSe₂ depending on selenium thin film thickness. Morphology of these films was analyzed using Atomic Force Microscopy and Scanning Electron Microscopy. The elemental analysis was done using Energy Dispersive X-ray technique. Optical characterization of the thin films was done by optical transmittance spectra. The electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: Glass/ITO/CdS/AgSbSe₂/Ag was formed, in which CdS was deposited by chemical bath deposition. J-V characteristics of this PV structure showed V_oc=370 mV and J_sc=0.5 mA/cm² under illumination using a tungsten halogen lamp.