Band alignment and p-type doping of ZnSnN2
Date
2017-05-31
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American Physical Society
Abstract
Composed of earth-abundant elements, ZnSnN2 is a promising semiconductor for photovoltaic and
photoelectrochemical applications. However, basic properties such as the precise value of the band gap and
the band alignment to other semiconductors are still unresolved. For instance, reported values for the band gap
vary from 1.4 to 2.0 eV. In addition, doping in ZnSnN2 remains largely unexplored. Using density functional
theory with the Heyd-Scuseria-Ernzerhof hybrid functional, we investigate the electronic structure of ZnSnN2,
its band alignment to GaN and ZnO, and the possibility of p-type doping. We find that the position of the
valence-band maximum of ZnSnN2 is 0.39 eV higher than that in GaN, yet the conduction-band minimum is
close to that in ZnO, which suggests that achieving p-type conductivity is likely as in GaN, yet it may be difficult
to control unintentional n-type conductivity as in ZnO. Among possible p-type dopants, we explore Li, Na, and
K substituting on the Zn site. We show that while LiZn is a shallow acceptor, NaZn and KZn are deep acceptors,
which we trace back to large local relaxations around the Na and K impurities due to the atomic size mismatches.
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Citation
Wang, Tianshi, Chaoying Ni, and Anderson Janotti. "Band alignment and p-type doping of ZnSnN 2." Physical Review B 95.20 (2017): 205205.