Crystalline Antimony Selenide Thin Films for Optoelectronics through Photonic Curing

Thermal annealing is the most common postdeposition technique used to crystallize antimony selenide (Sb₂Se₃) thin films. However, due to slow processing speeds and a high energy cost, it is incompatible with the upscaling and commercialization of Sb₂Se₃ for future photovoltaics. Herein, for the first time, a fast-annealing technique that uses millisecond light pulses to deliver energy to the sample is adapted to cure thermally evaporated Sb₂Se₃ films. This study demonstrates how photonic curing (PC) conditions affect the outcome of Sb₂Se₃ phase conversion from amorphous to crystalline by evaluating the films' crystalline, morphological, and optical properties. We show that Sb₂Se₃ is readily converted under a variety of different conditions, but the zone where suitable films for optoelectronic applications are obtained is a small region of the parameter space. Sb₂Se₃ annealing with short pulses (<3 ms) shows significant damage to the sample, while using longer pulses (>5 ms) and a 4-5 J cm^-2 radiant energy produces (211)- and (221)-oriented crystalline Sb₂Se₃ with minimal to no damage to the sample. A proof-of-concept photonically cured Sb₂Se₃ photovoltaic device is demonstrated. PC is a promising annealing method for large-area, high-throughput annealing of Sb₂Se₃ with various potential applications in Sb₂Se₃ photovoltaics.