Embodiments of the present invention include a method. The method includes heating a layer stack. The layer stack includes a first layer comprising cadmium and tin, a metal layer disposed over the first layer, and a window layer disposed over the metal layer. Heating the stack includes transforming at least a portion of the first layer from an amorphous phase to a crystalline phase. Heating may be performed using any of various configurations, such as, for example, heating an individual stack, or using a face-to-face configuration of multiple stacks. The stack may be used for fabricating a photovoltaic device.