Structural and electric properties of CuSbS₂ compound semiconductor bulk crystals

Abstract

Copper antimony disulfide (CuSbS2) is a promising candidate for solar absorber material owing to its high photoabsorption property and earth-abundant constituent elements. In this study, we fabricated CuSbS2 crystals of various nonstoichiometric compositions and investigated their optical and electric properties for their applications in photovoltaic devices. Band gap energies of CuSbS2 crystals thus-obtained were almost constant (ca. 1.5 eV) irrespective of their compositions. Hall-resistivity measurements exhibited that a CuSbS2 crystal with the compositional formula of 1.03/1.00/1.86 showed the best properties among the samples prepared in this study: the resistivity, hole concentration, and mobility of the sample were 1.4 Ω cm, 6.0 × 1016 cm−3, and 7.4 cm2 V−1 s−1, respectively. Although further optimization would be expected, the obtained properties are suitable for an absorber of photovoltaics.

Formation of Near-IR Excitons in Low-Dimensional CuSbS2

“…Thin-film materials for solar photovoltaics are challenging traditional wafer silicon in the renewable energy sector. − Scarcity and competing industrial demands for the constituent elements of CdTe and copper indium gallium disulfide/diselenide devices have driven the search for alternative systems with comparable performance. − Among them, CuSbS 2 is a promising material formed by earth-abundant elements and characterized by a large absorption coefficient at relevant frequencies for solar light harvesting. , The optical gap of bulk CuSbS 2 ranges between 1.3 and 1.5 eV. ,− Theoretical studies based on quantum density functional theory (DFT) calculations , have shown that in this material the fundamental gap is indirect, like in bulk silicon, and that the direct gap appears at a marginally higher energy of 1.73 eV. − …”