Dual-Wavelength Time-Resolved Photoluminescence Study of CdSexTe1-x Surface Passivation via MgyZn1-yO and Al2O3

Deborah McGott, Brian Good, Brian Fluegel, Joel Duenow, Colin Wolden, Matthew Reese

Research output: Contribution to journalArticlepeer-review

10 Scopus Citations

Abstract

Voltage loss is currently one of the biggest challenges facing cadmium telluride (CdTe) based photovoltaics. Determining the location(s) of major voltage loss within the device stack (e.g., front/back interface, grain boundaries) is therefore of primary interest. Here, we present a custom-built time-resolved photoluminescence system with two excitation wavelengths - 670 (standard) and 405 nm - to probe the device stack at depths of approximately 130 and 35 nm, respectively; their comparison helps differentiate interface and bulk contributions to carrier lifetime. We apply this system to examine the passivation effect of two significant recent advances in CdTe: the incorporation of Se to form graded CdSexTe1-x and the replacement of CdS with MgyZn1-yO. It is found that x = 0.2 Se is required to obtain lifetime improvements, primarily in the bulk. Additionally, evidence for trapping at the MgyZn1-yO/CdSexTe1-x interface was observed. This indicates further work is required to sufficiently passivate the front interface.

Original languageAmerican English
Pages (from-to)309-315
Number of pages7
JournalIEEE Journal of Photovoltaics
Volume12
Issue number1
DOIs
StatePublished - 1 Jan 2022

Bibliographical note

Publisher Copyright:
© 2011-2012 IEEE.

NREL Publication Number

  • NREL/JA-5K00-80301

Keywords

  • Cadmium telluride (CdTe)
  • CdSeTe
  • Front interface
  • MgZn O (MZO)
  • Time-resolved photoluminescence (TRPL)

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