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Title: Combinatorial Insights into Doping Control and Transport Properties of Zinc Tin Nitride

ZnSnN2 is an Earth-abundant semiconductor analogous to the III–nitrides with potential as a solar absorber due to its direct bandgap, steep absorption onset, and disorder-driven bandgap tunability. Despite these desirable properties, discrepancies in the fundamental bandgap and degenerate n-type carrier density have been prevalent issues in the limited amount of literature available on this material. We we use a combinatorial RF co-sputtering approach, we explored a growth-temperature-composition space for Zn1+xSn1-xN2 over the ranges 35–340 °C and 0.30–0.75 Zn/(Zn + Sn). In this way, we identified an optimal set of deposition parameters for obtaining as-deposited films with wurtzite crystal structure and carrier density as low as 1.8 × 1018 cm-3. Films grown at 230 °C with Zn/(Zn + Sn) = 0.60 were found to have the largest grain size overall (70 nm diameter on average) while also exhibiting low carrier density (3 × 1018 cm-3) and high mobility (8.3 cm2 V-1 s-1). Using this approach, we establish the direct bandgap of cation-disordered ZnSnN2 at 1.0 eV. Moreover, we report tunable carrier density as a function of cation composition, in which lower carrier density is observed for higher Zn content. Consequently, this relationship manifests as a Burstein–Moss shift widening the apparent bandgapmore » as cation composition moves away from Zn-rich. Collectively, these findings provide important insight into the fundamental properties of the Zn–Sn–N material system and highlight the potential to utilize ZnSnN2 for photovoltaics.« less
 [1] ;  [2] ;  [2] ;  [3] ;  [2] ;  [2] ;  [2] ;  [1] ;  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. Harvey Mudd College, Claremont, CA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 2050-7526
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Materials Chemistry. C; Journal Volume: 3; Journal Issue: 42; Related Information: Journal of Materials Chemistry C
Royal Society of Chemistry
Research Org:
National Renewable Energy Laboratory (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
14 SOLAR ENERGY; 36 MATERIALS SCIENCE direct bandgap; wurtzite crystal structure; carrier density; zinc tin nitride; Zn-Sn-N