Charging and discharging of defect states in CIGS/ZnO junctions

A. E. Delahoy, A. Ruppert, M. Contreras

Research output: Contribution to journalConference articlepeer-review

24 Scopus citations


The formation of photovoltaic junctions in thin film CIGS has been explored through the deposition of ZnO directly onto the CIGS by the reaction of Zn and atomic oxygen. Most of these devices exhibit strong light soaking effects in which Voc (at 1 sun) can increase from 250 mV to over 550 mV. A 12.3% efficient ZnO/CIGS solar cell was achieved. The soaking effect, which is the main topic of this paper, was found to be bias or field driven. Detailed investigations were conducted using a `drive and interrogate' procedure, in which the device is driven between two steady states corresponding to two different voltage biases, with brief interrogation of Voc at various times. Data spanning the temperature range 31-125 °C were acquired. It was found that the Voc versus log(t) relaxation curves can be described by a stretched exponential, and scale with t·exp(-E/kT) as a parameter, yielding E = 0.51 eV. Junction capacitance data are also reported. The underlying process, whether electronic or ionic, possesses a wide range of time constants.

Original languageEnglish (US)
Pages (from-to)140-144
Number of pages5
JournalThin Solid Films
StatePublished - Feb 21 2000
Externally publishedYes
EventThe 1999 E-MRS Spring Conference, Symposium O: Chalcogenide Semicondutors for Photovoltaics - Strasbourg, France
Duration: Jun 1 1999Jun 4 1999

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry


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