Estimation of front and back junctions of CZTSe:Ge solar cells by combined modulus and impedance spectroscopy

Sanghyun Lee, Kent J. Price, Edgardo Saucedo

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We have fabricated and investigated CTSe:Ge bi-layer devices by modulus spectroscopy combined with impedance spectroscopy to understand the electrical properties of hetero- and back-contact junctions. The equivalent circuit model is developed to decouple the properties of each junction at different frequency ranges. Modeling and numerical simulations with the in-house MATLAB modeling suites connected to external simulators, such as Sentaurus TCAD and LEVM/LEVMW software are conducted to estimate the impact of each junction component to modulus and impedance spectroscopy with a parallel equivalent circuit combination of resistance and capacitance components. The fabricated devices show doping concentration of 6.4 1015/cm3, and the conversion efficiency is 8.1% based on capacitance-voltage and current-voltage characterization. From the characterization and modeling, the built-in potential of the hetero-junction is estimated as 801 meV, which is ∼10% smaller than the ideal case from TCAD, 894 meV. Conversely, the built-in potential of the back contact junction is 428 meV. The total apparent built-in potential is estimated to be 373 meV from the Mott-Schottky equation.

Original languageEnglish
Article number335501
JournalJournal of Physics D: Applied Physics
Issue number33
StatePublished - Aug 2021

Bibliographical note

Publisher Copyright:
© 2021 IOP Publishing Ltd.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films


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