Tuning Electrical, Optical, and Thermal Properties through Cation Disorder in Cu2ZnSnS4

Journal Article · Mon Sep 23 00:00:00 EDT 2019 · Chemistry of Materials

DOI:https://doi.org/10.1021/acs.chemmater.9b02287· OSTI ID:1596251

Ye, Kevin ^[1]; Siah, Sin Cheng ^[1]; Erslev, Pater T; Akey, Austin ^[2]; Settens, Charles ^[1]; Bin Hoque, Md Shafkat ^[3]; Braun, Jeffrey ^[3]; Hopkins, Patrick ^[3]; Teeter, Glenn R ^[4]; Buonassisi, Tonio ^[1]; Jaramillo, R. ^[1]

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1. Massachusetts Institute of Technology
2. Harvard University
3. University of Virginia
4. National Renewable Energy Laboratory (NREL), Golden, CO (United States)

Chemical disorder in semiconductors is important to characterize reliably because it affects materials performance, for instance by introducing potential fluctuations and recombination sites. It also represents a means to control material properties, to far exceed the limits of equilibrium thermodynamics. We present a study of highly disordered Cu-Zn-Sn-S (d-CZTS) films along the Cu2SnS3-Cu2ZnSnS4-ZnS binary line, deposited by physical vapor deposition. Deposition at low temperature kinetically stabilizes compositions that are well outside of the narrow, equilibrium solid solution of kesterite (Cu2ZnSnS4). Here we study d-CZTS and its thermal treatment using complementary characterization techniques: X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). We find that cations in d-CZTS are highly disordered while the sulfur anions remain in a well-defined, cubic close-packed lattice. On the atomic scale, composition fluctuations are accommodated preferentially by stacking faults. Kinetically-stabilized cation disorder can produce nonequilibrium semiconductor alloys with a wide range of band gap, electronic conductivity, and thermal conductivity. d-CZTS therefore represents a processing route to optimizing materials for optoelectronic device elements such as light absorbers, window layers, and thermal barriers.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1596251
• Report Number(s): NREL/JA-5K00-75150
• Journal Information: Chemistry of Materials, Vol. 31, Issue 20
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
characterization techniques
chemical disorder
composition fluctuations
control materials
electronic conductivity
equilibrium thermodynamics
materials performance
potential fluctuations