Silicon Heterojunction Solar Cells with Epitaxial Buffer Layer on Textured Substrates

In the present work we report recent results for silicon heterojunction solar cells deposited by conventional Plasma Enhanced Chemical Vapor Deposition (PECVD) technique on textured Czochralski (CZ) silicon wafers. A new texturing technique was developed using a wet anisotropic chemical etching with a tetramethyl-ammonium hydroxide (TMAH) solution. An increase of the device photogenerated current, with maximum short circuit current of more then 36 mA/cm2 was attained. A study of the first stages of device layer growth is presented with relation to plasma ignition in PECVD systems. An original passivation technique of the amorphous/crystalline interface defects was implemented for textured wafers. Using this scheme a reproducible efficiency in excess of 16% was obtained on CZ textured wafers