Formation of CuInSe2 absorber by rapid thermal processing of electron-beam evaporated stacked elemental layers

Abstract

Copper indium diselenide (CuInSe2) film was formed using the rapid thermal process (RTP) of electron-beam (E-beam) evaporated Cu-In stacked elemental layers as an absorber layer for chalcopyrite solar cells. The E-beam evaporation method could accurately control the thickness of each elemental layer so that the chemical composition of Cu-In precursor could also be controlled by changing the thickness ratio of the Cu/In metal layer. The device-quality Cu-deficient CuInSe2 film was obtained when the thickness ratio of Cu/In was about 1/2.5. Otherwise, the RTP process time was also certified as one of the most important parameters of RTP when the temperature was over 550 degrees C. A single-phase CuInSe2 was successfully obtained after rapid thermal process under 580 degrees C for 3 min. Finally, the growth mechanism of CuInSe2 film during RTP process was also summarized.