A method of forming a semiconductor material of a photovoltaic device that includes providing a surface of a hydrogenated amorphous silicon containing material, and annealing the hydrogenated amorphous silicon containing material in a deuterium containing atmosphere. Deuterium from the deuterium-containing atmosphere is introduced to the lattice of the hydrogenated amorphous silicon containing material through the surface of the hydrogenated amorphous silicon containing material. In some embodiments, the deuterium that is introduced to the lattice of the hydrogenated amorphous silicon containing material increases the stability of the hydrogenated amorphous silicon containing material.