CUINSE2 FILM GROWTH USING PRECURSORS DEPOSITED AT LOW-TEMPERATURE

A sequential deposition process for CuInSe2 leading to highly efficien t thin film solar cells is described. Secondary phases and interdiffus ion determine the growth mechanism of a process consisting of InSex an d Cu deposition at a low substrate temperature followed by a high temp erature selenization step. A model which clearly shows the difference between Cu-rich and Cu-poor growth is described. It is shown that sodi um is mainly incorporated at the grain boundaries. Devices based on ab sorber layers produced by the new process exhibit efficiencies close t o 14% for CuInSe2.