Carrier-Induced Band-Gap Variation and Point Defects in Zn3 N2 from First Principles

Yu Kumagai, Kou Harada, Hirofumi Akamatsu, Kosuke Matsuzaki, Fumiyasu Oba

研究成果: Contribution to journalArticle査読

18 被引用数 (Scopus)


The zinc nitride Zn3N2 is composed of inexpensive and earth-abundant Zn and N elements and shows high electron mobility exceeding 100 cm2 V-1 s-1. Although various technological applications of Zn3N2 have been suggested so far, the synthesis of high-quality Zn3N2 samples, especially single crystals, is still challenging, and therefore its basic properties are not yet well understood. Indeed, the reported band gaps of as-grown Zn3N2 widely scatter from 0.85 to 3.2 eV. In this study, we investigate the large gap variation of Zn3N2 in terms of the Burstein-Moss (BM) effect and point-defect energetics using first-principles calculations. First, we discuss the relation between electron carrier concentration and optical gaps based on the electronic structure obtained using the Heyd-Scuseria-Ernzerhof hybrid functional. The calculated fundamental band gap is 0.84 eV in a direct-type band structure. Second, thermodynamic stability of Zn3N2 is assessed using the ideal-gas model in conjunction with the rigid-rotor model for gas phases and first-principles phonon calculations for solid phases. Third, carrier generation and compensation by native point defects and unintentionally introduced oxygen and hydrogen impurities are discussed. The results suggest that a significant BM shift occurs mainly due to oxygen substitutions on nitrogen sites and hydrogen interstitials. However, gaps larger than 2.0 eV would not be due to the BM shift because of the Fermi-level pinning caused by acceptorlike zinc vacancies and hydrogen-on-zinc impurities. Furthermore, we discuss details of peculiar defects such as a nitrogen-on-zinc antisite with azidelike atomic and electronic structures.

ジャーナルPhysical Review Applied
出版ステータス出版済み - 7 14 2017

All Science Journal Classification (ASJC) codes

  • 物理学および天文学(全般)


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