Development of plasma enhanced closed space sublimation for the deposition of CdS:O in CdTe solar cells

A hollow-cathode plasma-enhanced close space sublimation (PECSS) source was utilized to modify the CdS window layer material as it was being deposited for CdTe Solar cell fabrication. This was done by integrating PECSS into the CSU inline CdS/CdTe-cell fabricating system and by sublimating the CdS semiconductor material through a plasma discharge. To date oxygenated CdS (CdS:O) cells have been grown by sublimating CdS through a PECSS source operated on oxygen. Data are presented showing that PECSS CdS:O films have increased the band gap of the window layer therefore reducing absorption loss, increasing cell current, and improving efficiency by 1.2%.