Abstract: A method for synthesizing a thin film of copper, zinc, tin, and a chalcogen species (“CZTCh” or “CZTSS”) with well-controlled properties. The method includes depositing a thin film of precursor materials, e.g., approximately stoichiometric amounts of copper (Cu), zinc (Zn), tin (Sn), and a chalcogen species (Ch). The method then involves re-crystallizing and grain growth at higher temperatures, e.g., between about 725 and 925 degrees K, and annealing the precursor film at relatively lower temperatures, e.g., between 600 and 650 degrees K. The processing of the precursor film takes place in the presence of a quasi-equilibrium vapor, e.g., Sn and chalcogen species. The quasi-equilibrium vapor is used to maintain the precursor film in a quasi-equilibrium condition to reduce and even prevent decomposition of the CZTCh and is provided at a rate to balance desorption fluxes of Sn and chalcogens.

Abstract: A method for synthesizing a thin film of CZTS such as for use as an absorber in a photovoltaic device. The method includes providing a substrate in a chamber, and, then, depositing a film of CZTS material on the substrate, the CZTS material comprising copper, zinc, tin, and at least on chalcogen species. The depositing includes tuning an optical bandgap of the film with heterovalent alloying. The depositing is performed at low temperatures with the substrate provided in the chamber free of direct/active heating. For example, the substrate may be maintained at a temperature below about 150° C. during the depositing of the film. The heterovalent alloying involves controlling deposition rates for the copper and the zinc to define a copper to zinc ratio set the optical bandgap such as a value between about 1.0 eV and about 2.75 eV.

Abstract: A method for synthesizing a thin film of copper, zinc, tin, and a chalcogen species (“CZTCh” or “CZTSS”) with well-controlled properties. The method includes depositing a thin film of precursor materials, e.g., approximately stoichiometric amounts of copper (Cu), zinc (Zn), tin (Sn), and a chalcogen species (Ch). The method then involves re-crystallizing and grain growth at higher temperatures, e.g., between about 725 and 925 degrees K, and annealing the precursor film at relatively lower temperatures, e.g., between 600 and 650 degrees K. The processing of the precursor film takes place in the presence of a quasi-equilibrium vapor, e.g., Sn and chalcogen species. The quasi-equilibrium vapor is used to maintain the precursor film in a quasi-equilibrium condition to reduce and even prevent decomposition of the CZTCh and is provided at a rate to balance desorption fluxes of Sn and chalcogens.