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Title: Measurement of Carrier Dynamics in Photovoltaic CZTSe by Time-Resolved Terahertz Spectroscopy
We demonstrate the use of time-resolved terahertz spectroscopy coupled with numerical modeling of the transport equations to elucidate photoexcited carrier dynamics in a photovoltaic absorber. By measuring a high-quality Cu2ZnSnSe4 single crystal that exhibited device efficiency of 8.6%, we show that critical parameters including mobility, surface recombination velocity, and Shockley-Read-Hall lifetime can be obtained. Mobility values of 80 cm2/Vs were validated with Hall effect measurements. Surface recombination velocity could be reduced by at least two orders of magnitude, to 10^4 cm/s, with appropriate chemical and mechanical polishing. Carrier lifetimes exceeding 10 ns indicate promise for devices with high photovoltage. Terahertz spectroscopy provides complementary insight to conventional time-resolved photoluminescence and is particularly valuable for materials that are not strongly emissive.  more » « less
Award ID(s):
1507988
PAR ID:
10062218
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Conference record of the IEEE Photovoltaic Specialists Conference
Volume:
2017
ISSN:
0160-8371
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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