文摘
Copper antimony sulfide (CuSbSb>2b>) has been gaining traction as an earth-abundant absorber for thin-film photovoltaics given its near ideal band gap for solar energy conversion (∼1.5 eV), large absorption coefficient (>104 cm–1), and elemental abundance. Through careful in situ analysis of the deposition conditions, a low-temperature route to CuSbSb>2b> thin films via atomic layer deposition has been developed. After a short (15 min) postprocess anneal at 225 °C, the ALD-grown CuSbSb>2b> films were crystalline with micron-sized grains, exhibited a band gap of 1.6 eV and an absorption coefficient >104 cm–1, as well as a hole concentration of 1015 cm–3. Finally, the ALD-grown CuSbSb>2b> films were paired with ALD-grown TiOb>2b> to form a photovoltaic device. This photovoltaic device architecture represents one of a very limited number of Cd-free CuSbSb>2b> PV device stacks reported to date, and it is the first to demonstrate an open-circuit voltage on par with CuSbSb>2b>/CdS heterojunction PV devices. While far from optimized, this work demonstrates the potential for ALD-grown CuSbSb>2b> thin films in environmentally benign photovoltaics.