ABSTRACT
Processes for the formation of CIS photovoltaic device absorber films universally intend to form the chalcopyrite Cu-III-VI2, α-phase.Prior studies have shown, however, that other phases, both stable and metastable, are essential to the kinetics of device quality absorber film formation. Furthermore some phases remain in the completed films as unintended byproducts with mostly indeterminate effects on electronic transport. A discussion is presented of recent results in this field from a thermochemical perspective. A model for the phase chemistry of sodium in CIS films is presented. Some implications of our investigations of the thermochemistry in the Cu-In-Se ternary, Na-Cu-In-Se quaternary, and constituent unary and binary systems with respect to the intentional engineering of precursors and reaction strategies for the synthesis of CIS absorber films with improved quality are presented.
