Time-Resolved Correlative Optical Microscopy of Charge-Carrier Transport, Recombination, and Space-Charge Fields in CdTe Heterostructures: Article No. 083905

Darius Kuciauskas, Teresa Barnes, Thomas Myers, Alyssa Allende Motz

Research output: Contribution to journalArticlepeer-review

19 Scopus Citations

Abstract

From time- and spatially resolved optical measurements, we show that extended defects can have a large effect on the charge-carrier recombination in II-VI semiconductors. In CdTe double heterostructures grown by molecular beam epitaxy on the InSb (100)-orientation substrates, we characterized the extended defects and found that near stacking faults the space-charge field extends by 2-5 um. Charge carriers drift (with the space-charge field strength of 730-1,360 V cm-1) and diffuse (with the mobility of 260 +/- 30 cm2 V-1 s-1) toward the extended defects, where the minority-carrier lifetime is reduced from 560 ns to 0.25 ns. Therefore, the extended defects are nonradiative recombination sinks that affect areas significantly larger than the typical crystalline grains in II-VI solar cells. From the correlative time-resolved photoluminescence and second-harmonic generation microscopy data, we developed a band-diagram model that can be used to analyze the impact of extended defects on solar cells and other electronic devices.
Original languageAmerican English
Number of pages5
JournalApplied Physics Letters
Volume110
Issue number8
DOIs
StatePublished - 2017

NREL Publication Number

  • NREL/JA-5900-67479

Keywords

  • charge carriers
  • heterojunctions
  • photoluminescence
  • second harmonic generation
  • solar cells

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