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Title: Minority and Majority Charge Carrier Mobility in Cu 2ZnSnSe 4 revealed by Terahertz Spectroscopy

Here, the mobilities of electrons and holes determine the applicability of any semiconductor, but their individual measurement remains a major challenge. Here, we show that time-resolved terahertz spectroscopy (TRTS) can distinguish the mobilities of minority and majority charge carriers independently of the doping-type and without electrical contacts. To this end, we combine the well-established determination of the sum of electron and hole mobilities from photo-induced THz absorption spectra with mobility-dependent ambipolar modeling of TRTS transients. The method is demonstrated on a polycrystalline Cu 2ZnSnSe 4 thin film and reveals a minority (electron) mobility of 128 cm 2/V-s and a majority (hole) carrier mobility of 7 cm 2/V-s in the vertical transport direction relevant for light emitting, photovoltaic and solar water splitting devices. Additionally, the TRTS analysis yields an effective bulk carrier lifetime of 4.4 ns, a surface recombination velocity of 6 * 10 4 cm/s and a doping concentration of ca. 10 16 cm -3, thus offering the potential for contactless screen novel optoelectronic materials.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ; ORCiD logo [1]
  1. Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Report Number(s):
NREL/JA-5K00-72460
Journal ID: ISSN 2045-2322
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; mobility; terahertz; spectroscopy; CZTS; kesterite
OSTI Identifier:
1476709

Hempel, Hannes, Hages, Charles J., Eichberger, Rainer, Repins, Ingrid L., and Unold, Thomas. Minority and Majority Charge Carrier Mobility in Cu2ZnSnSe4 revealed by Terahertz Spectroscopy. United States: N. p., Web. doi:10.1038/s41598-018-32695-6.
Hempel, Hannes, Hages, Charles J., Eichberger, Rainer, Repins, Ingrid L., & Unold, Thomas. Minority and Majority Charge Carrier Mobility in Cu2ZnSnSe4 revealed by Terahertz Spectroscopy. United States. doi:10.1038/s41598-018-32695-6.
Hempel, Hannes, Hages, Charles J., Eichberger, Rainer, Repins, Ingrid L., and Unold, Thomas. 2018. "Minority and Majority Charge Carrier Mobility in Cu2ZnSnSe4 revealed by Terahertz Spectroscopy". United States. doi:10.1038/s41598-018-32695-6. https://www.osti.gov/servlets/purl/1476709.
@article{osti_1476709,
title = {Minority and Majority Charge Carrier Mobility in Cu2ZnSnSe4 revealed by Terahertz Spectroscopy},
author = {Hempel, Hannes and Hages, Charles J. and Eichberger, Rainer and Repins, Ingrid L. and Unold, Thomas},
abstractNote = {Here, the mobilities of electrons and holes determine the applicability of any semiconductor, but their individual measurement remains a major challenge. Here, we show that time-resolved terahertz spectroscopy (TRTS) can distinguish the mobilities of minority and majority charge carriers independently of the doping-type and without electrical contacts. To this end, we combine the well-established determination of the sum of electron and hole mobilities from photo-induced THz absorption spectra with mobility-dependent ambipolar modeling of TRTS transients. The method is demonstrated on a polycrystalline Cu2ZnSnSe4 thin film and reveals a minority (electron) mobility of 128 cm2/V-s and a majority (hole) carrier mobility of 7 cm2/V-s in the vertical transport direction relevant for light emitting, photovoltaic and solar water splitting devices. Additionally, the TRTS analysis yields an effective bulk carrier lifetime of 4.4 ns, a surface recombination velocity of 6 * 104 cm/s and a doping concentration of ca. 1016 cm-3, thus offering the potential for contactless screen novel optoelectronic materials.},
doi = {10.1038/s41598-018-32695-6},
journal = {Scientific Reports},
number = 1,
volume = 8,
place = {United States},
year = {2018},
month = {9}
}

Works referenced in this record:

Photovoltaic Materials and Devices Based on the Alloyed Kesterite Absorber (AgxCu1-x)2 ZnSnSe4
journal, March 2016
  • Gershon, Talia; Lee, Yun Seog; Antunez, Priscilla
  • Advanced Energy Materials, Vol. 6, Issue 10, Article No. 1502468
  • DOI: 10.1002/aenm.201502468