CdS barrier to minimize Zn loss during CdCl2 treatment of Cd-Zn-Te absorbers
journal contributionposted on 18.12.2018, 10:02 by Tushar M. Shimpi, Drew E. Swanson, Jennifer Drayton, Ali AbbasAli Abbas, Michael WallsMichael Walls, Kurt L. Barth, Walajabad S. Sampath
© 2018 A major challenge in the fabrication of high band gap II–VI polycrystalline solar cells is to preserve the original composition of the absorber after the CdCl2 activation treatment. In this study, a method is demonstrated to maintain the Cd-Zn-Te alloy absorber composition during its exposure to the CdCl2 treatment. A thin film of CdS was applied as a barrier on the back surface of the high band gap polycrystalline Cd(1−x)ZnxTe (x = 20% by atomic ratio, corresponding band gap 1.72 eV) before the CdCl2 treatment. Using transmission electron microscopy and energy dispersive spectroscopy, it was observed that the composition of Cd-Zn-Te was maintained after the CdCl2 treatment. The devices fabricated after removing the thin film of CdS, exhibited diode-like behavior. A significant increase in the quantum efficiency near the short wavelength region was observed, and the band gap of Cd(1−x)ZnxTe was maintained.
The co-sublimation and device fabrication work at Colorado State University was funded by Nation Science Foundation: Accelerating Innovation Research and Industry/University Cooperative Research Centers programs. The specimen preparation and TEM/EDS analysis at Loughborough University was supported by Engineering and Physical Science Research Council - Supergen SuperSolar Hub.
- Mechanical, Electrical and Manufacturing Engineering