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

doi:10.1063/1.5038160

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

Research output: Contribution to journal › Article

1 Citation (Scopus)

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 language	English
Article number	101904
Journal	Applied Physics Letters
Volume	113
Issue number	10
DOIs	https://doi.org/10.1063/1.5038160
Publication status	Published - Sep 3 2018

Fingerprint

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

Ikoma, Y., Chon, B., Yamasaki, T., Takahashi, K., Saito, K., Guo, Q., & Horita, Z. (2018). Crystal and electronic structural changes during annealing in severely deformed Si containing metastable phases formed by high-pressure torsion. Applied Physics Letters, 113(10), [101904]. https://doi.org/10.1063/1.5038160

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 journal › Article

Ikoma, Y, Chon, B, Yamasaki, T, Takahashi, K, Saito, K, Guo, Q & Horita, Z 2018, 'Crystal and electronic structural changes during annealing in severely deformed Si containing metastable phases formed by high-pressure torsion', Applied Physics Letters, vol. 113, no. 10, 101904. https://doi.org/10.1063/1.5038160

Ikoma Y, Chon B, Yamasaki T, Takahashi K, Saito K, Guo Q et al. Crystal and electronic structural changes during annealing in severely deformed Si containing metastable phases formed by high-pressure torsion. Applied Physics Letters. 2018 Sep 3;113(10). 101904. https://doi.org/10.1063/1.5038160

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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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.",

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