Metastable Defect Response in CZTSSe from Admittance Spectroscopy: Article No. 142105

Dean Levi, Mark Koeper, Charles Hages, Jian Li, Rakesh Agrawal

Research output: Contribution to journalArticlepeer-review

17 Scopus Citations


Admittance spectroscopy is a useful tool used to study defects in semiconductor materials. However, metastable defect responses in non-ideal semiconductors can greatly impact the measurement and therefore the interpretation of results. Here, admittance spectroscopy was performed on Cu2ZnSn(S,Se)4 where metastable defect response is illustrated due to the trapping of injected carriers into a deep defect state. To investigate the metastable response, admittance measurements were performed under electrically and optically relaxed conditions in comparison to a device following a low level carrier-injection pretreatment. The relaxed measurement demonstrates a single capacitance signature while two capacitance signatures are observed for the device measured following carrier-injection. The deeper level signature, typically reported for kesterites, is activated by charge trapping following carrier injection. Both signatures are attributed to bulk level defects. The significant metastable response observed on kesterites due to charge trapping obscures accurate interpretation of defect levels from admittance spectroscopy and indicates that great care must be taken when performing and interpreting this measurement on non-ideal devices.
Original languageAmerican English
Number of pages4
JournalApplied Physics Letters
Issue number14
StatePublished - 2017

NREL Publication Number

  • NREL/JA-5J00-70373


  • activation energies
  • chemical kinetics
  • dielectrics
  • garnet
  • spectroscopy


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