Inventors:
Glenn Teeter - Lakewood CO, US
Hui Du - Golden CO, US
Matthew Young - Lakewood CO, US
Assignee:
Alliance for Sustainable Energy, LLC - Golden CO
International Classification:
H01L 21/00
US Classification:
438 95, 438 57, 257436, 257E25009, 257E31029
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.