Crystal and electronic structural changes during annealing in severely deformed Si containing metastable phases formed by high-pressure torsion

Yoshifumi Ikoma, Bumsoo Chon, Terumasa Yamasaki, Kazutoshi Takahashi, Katsuhiko Saito, Qixin Guo, Zenji Horita

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Abstract

Single crystalline p- A nd n-type Si(100) wafers were severely deformed by high-pressure torsion (HPT) under a nominal pressure of 24 GPa. The HPT-processed samples consisted of metastable phases of body-centered-cubic Si-III and rhombohedral Si-XII, as well as diamond-cubic Si-I and amorphous phases. The photoemission spectroscopy using synchrotron radiation revealed that the valence band edge of the HPT-processed p- A nd n-type Si samples was located at ∼0.3 eV. Successive annealing in vacuum up to 200 °C led to the valence-band edge shift by ∼0.4 eV for both p- A nd n-type Si, and the disappearance of Si-III and Si-XII. These results indicated that the Si-III and Si-XII phases in the HPT-processed samples have smaller band gap than that of Si-I, and suggested that the valence-band edge shift after annealing is due to the mixture of Si-I and Si-IV phases in addition to the mid-gap pinning of the Fermi level.

Original languageEnglish
Article number101904
JournalApplied Physics Letters
Volume113
Issue number10
DOIs
Publication statusPublished - Sep 3 2018

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torsion
annealing
valence
electronics
crystals
shift
synchrotron radiation
photoelectric emission
diamonds
wafers
vacuum
spectroscopy

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

Cite this

Crystal and electronic structural changes during annealing in severely deformed Si containing metastable phases formed by high-pressure torsion. / Ikoma, Yoshifumi; Chon, Bumsoo; Yamasaki, Terumasa; Takahashi, Kazutoshi; Saito, Katsuhiko; Guo, Qixin; Horita, Zenji.

In: Applied Physics Letters, Vol. 113, No. 10, 101904, 03.09.2018.

Research output: Contribution to journalArticle

Ikoma, Yoshifumi ; Chon, Bumsoo ; Yamasaki, Terumasa ; Takahashi, Kazutoshi ; Saito, Katsuhiko ; Guo, Qixin ; Horita, Zenji. / Crystal and electronic structural changes during annealing in severely deformed Si containing metastable phases formed by high-pressure torsion. In: Applied Physics Letters. 2018 ; Vol. 113, No. 10.
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AU - Saito, Katsuhiko

AU - Guo, Qixin

AU - Horita, Zenji

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