Advances in the one-step synthesis of 2D and 3D sulfide materials grown by pulsed laser deposition assisted by a sulfur thermal cracker

Abstract

This paper presents advances in synthesizing sulfide thin films by a hybrid approach based on pulsed laser deposition (PLD) combined with a sulfur cracker beam. In one step, we demonstrate a facile and non-toxic method to fabricate two-dimensional (2D) materials of MoS₂ and sulfide kesterites of Cu₂ZnSnS₄ (CZTS), excluding some drawbacks such as toxic and expensive reactants or non-vacuum conditions susceptible to contamination. PLD has emerged as a catalyst-free method for the bottom-up synthesis of 2D materials, such as MoS₂. However, the main figure of merit, i.e., photoluminescence (PL) yield, is relatively low. Here, we demonstrate the high-temperature synthesis of mono- and multilayers of MoS₂ by enhanced sulfurization reaction via the supply of S₂ and larger clusters in a PLD process. We observed that the improved sulfurization increases the sulfur content in the films, as indicated by X-ray photoelectron spectroscopy (XPS). Moreover, the mono–bilayers MoS₂ produced by PLD assisted by a reactive sulfur beam exhibit a significantly enhanced PL emission. Secondly, we demonstrate the one-step synthesis of CZTS by PLD with the deposition of reactive sulfur molecules. The CZTS films were produced in a temperature range from room temperature up to 500 ℃. The composition of the films shows some variations with temperature, and the sulfur content is steadily between 47 and 52%. The growth temperature of 450 ℃ was identified as optimum for directly synthesizing high-quality CZTS films with a characteristic columnar structure. At 500 ℃, a substantial decomposition of CZTS and a complete Sn loss occurs. Our findings demonstrate that crystalline sulfide films can be grown successfully by combining PLD and deposition of reactive sulfur molecules in a non-toxic approach.