Amorphous oxides as electron transport layers in Cu(In, Ga)Se2 superstrate devices. Issue 5 (3rd February 2017)

• Record Type: Journal Article
• Authors: Heinemann, M. D.; van Hest, M. F. A. M.; Contreras, M.; Perkins, J. D.; Zakutayev, A.; Kaufmann, C. A.; Unold, T.; Ginley, D. S.; Berry, J. J.
• Is Part Of: Physica status solidi. Volume 214:Issue 5(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-02-03
• Subjects: amorphous oxides -- CuInGaSe2 -- Ga2O3 -- solar cells -- superstrate; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201600870
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Cu(In, Ga)Se2 (CIGS) solar cells in superstrate configuration promise improved light management and higher stability compared to substrate devices, but they have yet to deliver comparable power conversion efficiencies (PCEs). Chemical reactions between the CIGS layer and the front contact were shown in the past to deteriorate the p‐n junction in superstrate devices, which led to lower efficiencies compared to the substrate‐type devices. This work aims to solve this problem by identifying a buffer layer between the CIGS layer and the front contact, acting as the electron transport layer, with an optimized electron affinity, doping density and chemical stability. Using combinatorial material exploration we identified amorphous gallium oxide (a‐GaO x ) as a potentially suitable buffer layer material. The best results were obtained for a‐GaO x with an electron affinity that was found to be comparable to that of CIGS. Based on the results of device simulations, it is assumed that detrimental interfacial acceptor states are present at the interface between CIGS and a‐GaO x . However, these initial experiments indicate the potential of a‐GaO x in this application, and how to reach performance parity with substrate devices, by further increase of its n‐type doping density.