The present invention relates to method and apparatus for preparing thin films of materials for various applications including electronic devices such as solar cells. In one aspect, each of the method and apparatus passing an electrical current through at least one of the base or sheet to provide controlled localized heat to the base or sheet, or to layers disposed above the base or sheet. In another aspect, the controlled localized heat is provided in combination with a process environment that can be a non-inert gas that contains an element that will become part of a compound on the base or sheet, or an inert gas that allows for the process environment to provide annealing.