Structural, electrical and optical characteristics of CuSbSe2 films prepared by pulsed laser deposition and magnetron sputtering processes

Abstract

CuSbSe2 is emerging as an alternative absorber for thin-film photovoltaics owing to its intrinsic p-type conductivity, proper band gap (~ 1.1 eV), high-absorption coefficient (> 104 cm−1) and low cost. Moreover, it is nontoxic and its compositional elements (Cu, Se and Sb) are abundant in the crust of earth. In the present work, Sb2Se3/Cu multilayers were deposited by pulsed laser deposition (PLD) followed by magnetron sputtering (MS). After that, the as-prepared multilayers were annealed in-suit in the MS chamber at different temperatures and times to obtain high-quality CuSbSe2 ternary compound. Five intermetallic compounds were generated in this process, including CuSbSe2, Sb2Se3, CuSe2, Cu2Se and Cu3SbSe3. Besides, it was found out that most CuSbSe2 ternary compound was generated when the as-prepared multilayers were annealed at 420 °C for 10 min. The crystallite size of CuSbSe2 phase increased with elevating annealing temperature, while more holes and gaps occurred when the annealing temperature exceeded 420 °C. The results of energy-dispersive spectrometer indicated the film was highly developed with nearly stoichiometric atomic ratio of 27.91:22.72:49.37 (Cu:Sb:Se). The electrical measurement results revealed the semiconducting nature of the film and gave the conductivity activation energy of 0.26 eV, 0.08 eV and 0.13 eV, respectively. The direct band gap of the annealed film was revealed as 1.13 eV, which fulfilled the Shockley–Queisser requirements for the efficient harvesting of the solar spectrum.