Chemical composition and electronic properties of CuInS2/Zn(S,O) interfaces

Rodrigo Sáez-Araoz, Iver Lauermann, Axel Neisser, Martha Ch Lux-Steiner, Ahmed Ennaoui

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


We report on the chemical deposition and electronic properties of CuInS2/Zn(S,O) interfaces. The Zn(S,O) buffer was grown by a new chemical bath deposition (CBD) process that allows the tailoring of the S/O ratio in the films. Resulting Zn(S,O) films exhibit transparencies above 80% (for λ>390 nm) and an optical energy band gap of 3.9 eV which decreases to 3.6 eV after annealing in air at 200°C Production line CuInS2 (CIS) absorbers provided by Sulfurcell Solartechnik GmbH are used as substrates for the investigation of the CIS/Zn(S,O) interface and the chemical composition of Zn(S,O). A ZnS/(ZnS+ZnO) ratio of 0.5 is found by X-ray photoelectron spectroscopy and X-ray excited Auger electron spectroscopy (XPS and XAES). The valence band offset between the heterojunction partners (ΔEv =1.8 ± 0.2 eV) has been determined by means of XPS and ultraviolet photoelectron spectroscopy (UPS). Considering the energy band gap of the CIS absorber and the measured band gap of Zn(S,O), the conduction band offset (ΔEC) is calculated as: ΔEC=E g Zn(S,O)-Eg CIS-ΔEv resulting in a spike of 0.5±0.3 eV in the conduction band at the heterojunction before annealing. After the heat treatment, the valence band offset is reduced to 1.5±0.2 eV and the calculated conduction band offset remains at 0.5±0.3 eV.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium Proceedings
Number of pages7
Publication statusPublished - 2010
Externally publishedYes
Event2009 MRS Spring Meeting - San Francisco, CA, United States
Duration: 13 Apr 200917 Apr 2009


Other2009 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA


ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials

Cite this

Sáez-Araoz, R., Lauermann, I., Neisser, A., Lux-Steiner, M. C., & Ennaoui, A. (2010). Chemical composition and electronic properties of CuInS2/Zn(S,O) interfaces. In Materials Research Society Symposium Proceedings (Vol. 1165, pp. 101-107)