Impact of Dopant-Induced Optoelectronic Tails on Open-Circuit Voltage in Arsenic-Doped Cd(Se)Te Solar Cells

John Moseley, Sachit Grover, Dingyuan Lu, Gang Xiong, Harvey Guthrey, Mowafak Al-Jassim, Wyatt Metzger

Research output: Contribution to journalArticlepeer-review

27 Scopus Citations

Abstract

Fluctuations refer to inhomogeneity in the distribution of donors and acceptors at the nanometer scale and occur in many compound solar cell materials such as Cu(In,Ga)Se2, Cu2ZnSn(S,Se)4, and CdSexTe1-x. In this work, numerical simulations show that these fluctuations produce not only electrostatic potential variation, but also, local changes in the carrier density and effective bandgap. For a CdSexTe1-x absorber doped with arsenic, simulations and cathodoluminescence data within single grains demonstrate how donor and acceptor densities - consistent with capacitance-voltage and secondary-ion mass-spectrometry data - produce tails in photoluminescence, quantum efficiency, and absorption measurements. Using multiple theoretical approaches, we demonstrate that the fluctuations can hinder expected performance gains from increased carrier density, and we describe the significant open-circuit voltage deficit observed in the CdSexTe1-x:As solar technology. Our results demonstrate that it is critical to characterize and reduce carrier compensation to realize a higher efficiency.

Original languageAmerican English
Article number103105
Number of pages17
JournalJournal of Applied Physics
Volume128
Issue number10
DOIs
StatePublished - 14 Sep 2020

Bibliographical note

Publisher Copyright:
© 2020 Author(s).

NREL Publication Number

  • NREL/JA-5K00-76533

Keywords

  • band tails
  • potential fluctuations
  • thin-film solar cells

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