Advanced Co-sublimation of Low Bandgap CdSexTe1-x Alloy to Achieve Higher Short-Circuit Current

Over 19% device efficiency with over 28 mA/cm(2) short-circuit current density has been achieved with thin-film using CdSeTe/CdTe graded absorber. A deep pocket sublimation source was used to deposit CdSeTe alloy. However, cross-section line scan using energy dispersive X-ray spectroscope showed that actual Se incorporation in the absorber films was much lower than the feed stock composition. Further lowering the band-gap of deposited CdSeTe films will further improve absorption of higher wavelengths leading to higher short-circuit current density. To overcome the limitation preferential sublimation of CdSeTe, advanced co-sublimation of Se and CdTe to achieve higher Se incorporation and lower bandgap is presented.