Using heterostructural alloying to tune the structure and properties of the thermoelectric Sn1–xCaxSe
- Oregon State Univ., Corvallis, OR (United States)
- Univ. of Colorado, Boulder, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Colorado School of Mines, Golden, CO (United States)
We grow and kinetically stabilize the isotropic rocksalt phase of SnSe thin films by alloying SnSe with CaSe. Thin polycrystalline films of the metastable heterostructural alloy Sn1–xCaxSe are synthesized by pulsed laser deposition on amorphous SiO2 over the entire composition range 0 < x < 1. We observe the theoretically-predicted, composition-driven change from a layered, orthorhombic structure to an isotropic, cubic structure near x = 0.18, in reasonable agreement with the theoretical value of x = 0.13 calculated from first principles. The optical band gap is highly non-linear in x and the trend agrees with theory predictions. Compared to the layered end-member SnSe, the isotropic alloy near the orthorhombic-to-rocksalt transition has a p-type electrical resistivity three orders of magnitude lower, and a thermoelectric power factor at least ten times larger. Furthermore manipulation of the structure of a functional material like SnSe via alloying may provide a new path to enhanced functionality, in this case, improved thermoelectric performance.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Next Generation of Materials by Design: Incorporating Metastability (CNGMD)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1379467
- Alternate ID(s):
- OSTI ID: 1390296
- Report Number(s):
- NREL/JA--5K00-70057
- Journal Information:
- Journal of Materials Chemistry. A, Journal Name: Journal of Materials Chemistry. A Journal Issue: 32 Vol. 5; ISSN JMCAET; ISSN 2050-7488
- Publisher:
- Royal Society of ChemistryCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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