Exciton photoluminescence and benign defect complex formation in zinc tin nitride
- National Renewable Energy Lab. (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States)
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Colorado School of Mines, Golden, CO (United States)
- SLAC National Accelerator Lab., Menlo Park, CA (United States). Applied Energy Programs
Emerging photovoltaic materials need to prove their viability by demonstrating excellent electronic properties. In ternary and multinary semiconductors, disorder and off-stoichiometry often cause defects that limit the potential for high-efficiency solar cells. We report on Zn-rich ZnSnN2 (Zn/(Zn + Sn) = 0.67) photoluminescence, high-resolution X-ray diffraction, and electronic structure calculations based on Monte-Carlo structural models. The mutual compensation of Zn excess and O incorporation affords a desirable reduction of the otherwise degenerate n-type doping, but also leads to a strongly off-stoichiometric and disordered atomic structure. It is therefore remarkable that we observe only near-edge photoluminescence from well-resolved excitons and shallow donors and acceptors. Based on first principles calculations, this result is explained by the mutual passivation of ZnSn and ON defects that renders both electronically benign. The calculated bandgaps range between 1.4 and 1.8 eV, depending on the degree of non-equilibrium disorder. The experimentally determined value of 1.5 eV in post-deposition annealed samples falls within this interval, indicating that further bandgap engineering by disorder control should be feasible via appropriate annealing protocols.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
- Grant/Contract Number:
- 30302; AC02-76SF00515; AC36-08GO28308
- OSTI ID:
- 1476311
- Alternate ID(s):
- OSTI ID: 1457484
- Report Number(s):
- NREL/JA-5J00-71244; MHAOAL
- Journal Information:
- Materials Horizons, Vol. 5, Issue 5; ISSN 2051-6347
- Publisher:
- Royal Society of ChemistryCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Interplay between Composition, Electronic Structure, Disorder, and Doping due to Dual Sublattice Mixing in Nonequilibrium Synthesis of ZnSnN 2 :O
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journal | January 2019 |
Electron scattering mechanisms in polycrystalline sputtered zinc tin oxynitride thin films
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journal | July 2019 |
Ternary nitride semiconductors in the rocksalt crystal structure
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journal | July 2019 |
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