Chemical bath deposition and microstructuring of tin (II) sulfide films for photovoltaics

Tin (II) sulfide is prepared through chemical bath deposition and annealed in a hydrogen sulfide environment to produce thin films for photovoltaic devices. The grain size, composition, and morphology are controlled by tailoring the bath composition and annealing conditions. The films have stoichiometric composition, are oxygen-free, have an optical band gap below 1.2 eV, and have an orthorhombic crystal structure. Through this method, a variety of film morphologies can be deposited, from dense films to micro-crystalline porous materials, in which micro-structured platelets can be incorporated through a self-assembly process. Annealing treatments simultaneously increase crystal size and improve purity to more efficiently extract photo-generated carriers. Electronic properties of the films are presented as well as insights into device preparation.