Simultaneous Measurement of Minority-Carrier Lifetime in Single-Crystal CdTe Using Three Transient Decay Techniques

Steven Johnston, Richard Ahrenkiel, Darius Kuciauskas, David Albin, Wyatt Metzger, Katherine Zaunbrecher

Research output: Contribution to journalArticlepeer-review

25 Scopus Citations

Abstract

Minority-carrier lifetimes have simultaneously been measured on a single-crystal CdTe sample using three transient decay techniques. These measurements are microwave-reflection photoconductive decay (μ-PCD), time-resolved photoluminescence (TRPL), and transient free-carrier absorption (TFCA). The sample is a 0.8-mm-thick single-crystal CdTe sample from JX Nippon Mining & Metals USA, Inc., which is nominally undoped but has a hole concentration of about 2-3 × 1014 cm-3. Excess carriers are generated using a Nd:YAG laser with ∼5-ns pulses, and lifetimes are measured at room temperature. Using 532-nm excitation, the decay curves show an initial short-lifetime component, as carriers are generated near the unpassivated front surface. While TRPL shows a short lifetime of ∼7 ns, both μ-PCD and TFCA have relatively long single-exponential decays after the initial 100 ns response. These decay times, which are more dominated by the bulk lifetime after the initial surface recombination, are ∼190 ns for both μ-PCD and TFCA. Simultaneous measurements using two-photon (1064 nm) excitation show bulk-dominated recombination for all three techniques. Lifetimes for both μ-PCD and TFCA are 270 ns, while the TRPL lifetime, which still shows some surface-limited initial decay, is 160 ns.

Original languageAmerican English
Article number6870430
Pages (from-to)1295-1300
Number of pages6
JournalIEEE Journal of Photovoltaics
Volume4
Issue number5
DOIs
StatePublished - Sep 2014

NREL Publication Number

  • NREL/JA-5J00-61227

Keywords

  • Cadmium compounds
  • charge carrier lifetime
  • infrared detectors
  • microwave bands
  • photoconductivity
  • photoluminescence
  • photovoltaic cells
  • tellurium

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