Mechanochemical bulk synthesis and e-beam growth of thin films of Sb2Se3 photovoltaic absorber

Abstract

Antimonselite (Sb2Se3) bulk material has been prepared by mechanical alloying through ball milling of the elemental precursors antimony (Sb) and selenium (Se) in place of conventional solid state synthesis. X-ray diffraction (XRD), Raman spectroscopy studies and Energy dispersive spectroscopy (EDS) studies confirm the formation of polycrystalline Sb2Se3 along with elemental Sb. The as-milled bulk material was used as source to deposit Sb2Se3 thin films by e-beam deposition. Thin films have been grown at a substrate temperature of ∼373 K with an optimal electron beam current (Ib) of ∼30 mA at fixed voltage of ∼5 kV. The films were studied using XRD and Raman spectroscopy for the structural and phase analyses. Scanning electron microscopy (SEM) studies and energy dispersive spectroscopy (EDS) measurements revealed the formation of near stoichiometric thin films with smooth and uniform surface. Rutherford backscattered spectrometry (RBS) and proton induced X-ray emission spectroscopy (PIXE) tools were employed to confirm the chemical composition of as-grown Sb2Se3 thin films. Optical transmission spectrum showed a very sharp transition near the fundamental absorption edge ∼1.26 eV. The films exhibited an average absorption coefficient values exceeding > 104 cm−1 in the visible region making it a promising material for solar absorber in thin film solar cell.