TY - JOUR
T1 - Combinatorial Synthesis of Magnesium Tin Nitride Semiconductors
AU - Greenaway, Ann L.
AU - Loutris, Amanda L.
AU - Heinselman, Karen N.
AU - Melamed, Celeste L.
AU - Schnepf, Rekha R.
AU - Tellekamp, M. Brooks
AU - Woods-Robinson, Rachel
AU - Sherbondy, Rachel
AU - Bardgett, Dylan
AU - Bauers, Sage
AU - Zakutayev, Andriy
AU - Christensen, Steven T.
AU - Lany, Stephan
AU - Tamboli, Adele C.
N1 - Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/5/6
Y1 - 2020/5/6
N2 - Nitride materials feature strong chemical bonding character that leads to unique crystal structures, but many ternary nitride chemical spaces remain experimentally unexplored. The search for previously undiscovered ternary nitrides is also an opportunity to explore unique materials properties, such as transitions between cation-ordered and -disordered structures, as well as to identify candidate materials for optoelectronic applications. Here, we present a comprehensive experimental study of MgSnN2, an emerging II-IV-N2 compound, for the first time mapping phase composition and crystal structure, and examining its optoelectronic properties computationally and experimentally. We demonstrate combinatorial cosputtering of cation-disordered, wurtzite-type MgSnN2 across a range of cation compositions and temperatures, as well as the unexpected formation of a secondary, rocksalt-type phase of MgSnN2 at Mg-rich compositions and low temperatures. A computational structure search shows that the rocksalt-type phase is substantially metastable (>70 meV/atom) compared to the wurtzite-type ground state. Spectroscopic ellipsometry reveals optical absorption onsets around 2 eV, consistent with band gap tuning via cation disorder. Finally, we demonstrate epitaxial growth of a mixed wurtzite-rocksalt MgSnN2 on GaN, highlighting an opportunity for polymorphic control via epitaxy. Collectively, these findings lay the groundwork for further exploration of MgSnN2 as a model ternary nitride, with controlled polymorphism, and for device applications, enabled by control of optoelectronic properties via cation ordering.
AB - Nitride materials feature strong chemical bonding character that leads to unique crystal structures, but many ternary nitride chemical spaces remain experimentally unexplored. The search for previously undiscovered ternary nitrides is also an opportunity to explore unique materials properties, such as transitions between cation-ordered and -disordered structures, as well as to identify candidate materials for optoelectronic applications. Here, we present a comprehensive experimental study of MgSnN2, an emerging II-IV-N2 compound, for the first time mapping phase composition and crystal structure, and examining its optoelectronic properties computationally and experimentally. We demonstrate combinatorial cosputtering of cation-disordered, wurtzite-type MgSnN2 across a range of cation compositions and temperatures, as well as the unexpected formation of a secondary, rocksalt-type phase of MgSnN2 at Mg-rich compositions and low temperatures. A computational structure search shows that the rocksalt-type phase is substantially metastable (>70 meV/atom) compared to the wurtzite-type ground state. Spectroscopic ellipsometry reveals optical absorption onsets around 2 eV, consistent with band gap tuning via cation disorder. Finally, we demonstrate epitaxial growth of a mixed wurtzite-rocksalt MgSnN2 on GaN, highlighting an opportunity for polymorphic control via epitaxy. Collectively, these findings lay the groundwork for further exploration of MgSnN2 as a model ternary nitride, with controlled polymorphism, and for device applications, enabled by control of optoelectronic properties via cation ordering.
KW - combinatorial synthesis
KW - light-emitting diodes
KW - nitride semiconductors
KW - RF co-sputtering
UR - http://www.scopus.com/inward/record.url?scp=85084542153&partnerID=8YFLogxK
U2 - 10.1021/jacs.0c02092
DO - 10.1021/jacs.0c02092
M3 - Article
AN - SCOPUS:85084542153
SN - 0002-7863
VL - 142
SP - 8421
EP - 8430
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 18
ER -