Photovoltaic devices and methods for preparing a p-type semiconductor generally include electroplating a layer of gallium or a gallium alloy onto a conductive layer by contacting the conductive layer with a plating bath free of complexing agents including a gallium salt, methane sulfonic acid or sodium sulfate and an organic additive comprising at least one nitrogen atom and/or at least one sulfur atom, and a solvent; adjusting a pH of the solution to be less than 2.6 or greater than 12.6. The photovoltaic device includes an impurity in the p-type semiconductor layer selected from the group consisting of arsenic, antimony, bismuth, and mixtures thereof. Various photovoltaic precursor layers for forming CIS, CGS and CIGS p-type semiconductor structures can be formed by electroplating the gallium or gallium alloys in this manner. Also disclosed are processes for forming a thermal interface of gallium or a gallium alloy.