The activation of thin film CdTe solar cells using alternative chlorine containing compounds
journal contributionposted on 30.04.2015, 10:49 by Bianca Maniscalco, Ali Abbas, Jake Bowers, Piotr Kaminski, Kevin Bass, Geoff West, Michael Walls
The re-crystallisation of thin film cadmium telluride (CdTe) using cadmium chloride (CdCl2) is a vital process for obtaining high efficiency photovoltaic devices. However, the precise micro-structural mechanisms involved are not well understood. In this study, we have used alternative chlorine-containing compounds to determine if these can also assist the re-crystallisation of the CdTe layer and to understand the separate roles of cadmium and chlorine during the activation. The compounds used were: tellurium tetrachloride (TeCl4), cadmium acetate (Cd(CH3CO2)2), hydrochloric acid (HCl) and zinc chloride (ZnCl2). TeCl4was used to assess the role of Cl and the formation of a Te-rich outer layer which may assist the formation of the back contact. (Cd(CH3CO2)2) and HCl were used to distinguish between the roles of cadmium and chlorine in the process. Finally, ZnCl2was employed as an alternative to CdCl2. We report on the efficacy of using these alternative Cl-containing compounds to remove the high density of planar defects present in untreated CdTe.
The authors are grateful to Dr. K. Barth and Professor W.S. Sampath of the Colorado State University for the supply of CSS deposited thin film CdTe cells using their process of reference. The authors are also grateful to EPSRC (EP/J017361/1) for funding through the Supergen SuperSolar Hub.
- Mechanical, Electrical and Manufacturing Engineering
- Centre for Renewable Energy Systems Technology (CREST)