A method of depositing thin semiconductor films used to make certain types of photovoltaic devices. With this method, a substrateThe physical material upon which a photovoltaic cell is applied. is exposed to one or more vaporized compounds, one or more of which contain desirable constituents. A chemical reaction is initiated, at or near the substrateThe physical material upon which a photovoltaic cell is applied. surface, to produce the desired material that will condense on the substrateThe physical material upon which a photovoltaic cell is applied..