Thin films of zinc, selenium, and zinc-selenide (nonstoichiometric) have been deposited at room temperature on various substrates by the photodissociation of zinc dimethyl and selenium dimethyl with an incoherent light source. Large thicknesses (∼6000Å) and areas with 2-cm cross diameters have been produced. This low-temperature technique may provide a drastically improved method for depositing laser mirror thin films that have much higher quality and purity levels not heretofore available by the more conventional methods such as vacuum deposition, electron or ion beams.