Amorphous Oxides as Electron Transport Layers in Cu(In,Ga)Se2 Superstrate Devices

Marinus Van Hest, Andriy Zakutayev, David Ginley, Joseph Berry, M. Heinemann, C. Kaufmann, T. Unold, Miguel Contreras, John Perkins

Research output: Contribution to journalArticlepeer-review

12 Scopus Citations


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-GaOx) as a potentially suitable buffer layer material. The best results were obtained for a-GaOx 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-GaOx. However, these initial experiments indicate the potential of a-GaOx in this application, and how to reach performance parity with substrate devices, by further increase of its n-type doping density.

Original languageAmerican English
Article number1600870
Number of pages6
JournalPhysica Status Solidi (A) Applications and Materials Science
Issue number5
StatePublished - 2017

Bibliographical note

Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

NREL Publication Number

  • NREL/JA-5K00-68700


  • amorphous oxides
  • CuInGaSe
  • GaO
  • solar cells
  • superstrate


Dive into the research topics of 'Amorphous Oxides as Electron Transport Layers in Cu(In,Ga)Se2 Superstrate Devices'. Together they form a unique fingerprint.

Cite this