Difficulty of carrier generation in orthorhombic PbO

Min Liao, Seiji Takemoto, Zewen Xiao, Yoshitake Toda, Tomofumi Tada, Shigenori Ueda, Toshio Kamiya, Hideo Hosono

研究成果: Contribution to journalArticle査読

6 被引用数 (Scopus)

抄録

Polycrystalline β-PbO films were grown by pulsed laser deposition in atmospheres ranging from oxygen-poor (the oxygen pressure of 0.01 Pa) to oxygen-rich (13 Pa) conditions, and the oxygen chemical potential was further enhanced by ozone annealing to examine hole doping. It was found that each of the as-grown β-PbO films showed poor electrical conductivity, σ < 1.4 × 10-7 S cm-1, regardless of the oxygen pressure. The density functional calculations revealed that native defects including Pb and O vacancies have deep transition levels and extremely high formation enthalpies, which indicates difficulty of carrier generation in β-PbO and explains the experimentally observed poor electrical conductivity. The analysis of the electronic structures showed that the interaction between Pb 6s and O 2p orbitals is weak due to the deep energy level of Pb 6s and does not raise the valence band maximum (VBM) level unlike that observed in SnO, which is also supported by ultraviolet photoemission spectroscopy measurements. The deep acceptor transition levels of the native defects are attributed to the deep VBM of β-PbO. On the other hand, annealing β-PbO films in reactive oxygen-containing atmospheres (i.e., O3) led to a significantly enhanced electrical conductivity (i.e., σ > 7.1 × 102 S cm-1) but it is the result of the formation of an n-type PbO2 phase because oxygen chemical potential exceeded the phase boundary limit. The striking difference in carrier generation between PbO and SnO is discussed based on the electronic structures calculated by density functional theory.

本文言語英語
論文番号165701
ジャーナルJournal of Applied Physics
119
16
DOI
出版ステータス出版済み - 4 28 2016
外部発表はい

All Science Journal Classification (ASJC) codes

  • 物理学および天文学(全般)

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