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Title: Design of Metastable Tin Titanium Nitride Semiconductor Alloys

Here, we report on design of optoelectronic properties in previously unreported metastable tin titanium nitride alloys with spinel crystal structure. Theoretical calculations predict that Ti alloying in metastable Sn 3N 4 compound should improve hole effective mass by up to 1 order of magnitude, while other optical bandgaps remains in the 1–2 eV range up to x ~ 0.35 Ti composition. Experimental synthesis of these metastable alloys is predicted to be challenging due to high required nitrogen chemical potential (Δμ N ≥ +1.0 eV) but proven to be possible using combinatorial cosputtering from metal targets in the presence of nitrogen plasma. Characterization experiments confirm that thin films of such (Sn 1–xTi x) 3N 4 alloys can be synthesized up to x = 0.45 composition, with suitable optical band gaps (1.5–2.0 eV), moderate electron densities (10 17 to 10 18 cm –3), and improved photogenerated hole transport (by 5×). Overall, this study shows that it is possible to design the metastable nitride materials with properties suitable for potential use in solar energy conversion applications.
 [1] ; ORCiD logo [2] ;  [3] ;  [1] ;  [4] ;  [4] ;  [1] ;  [1] ; ORCiD logo [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States); San Diego State Univ., San Diego, CA (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States); Swiss Federal Labs. for Material Science and Technology, Dubendorf (Switzerland)
  4. Colorado School of Mines, Golden, CO (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0897-4756
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 15; Journal ID: ISSN 0897-4756
American Chemical Society (ACS)
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
14 SOLAR ENERGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; optoelectronics; semiconductor alloys; metastability
OSTI Identifier: