High Efficiency Solar Cells Based on CuGaInSe2 Thin Films Grown by Oscillating Temperature Selenization in a Se Vapour

CuInGaSe2/CdS thin film solar cells with efficiency larger than 14% have been prepared by a novel process. In-Cu-Ga elemental layers, deposited by an Electron-Gun on top of a Mo covered soda lime glass, were processed at high temperature in a Se vapor with the Oscillating Temperature Selenization method. In this way, a layer of pure CuInSe2 is formed on the film surface. In order to get a mixed CuInGaSe2 film, another layer, composed of 725 Å of Cu and 1200 Å of Ga, was deposited by Electron-Gun on top of the CuInSe2 film. This layer is processed again at high temperature in a Se vapor. The cell is completed by depositing a 300Å film of pure CdS followed by 1-2 μm film of In-doped CdS.