Ultrafast photocarrier dynamics related to defect states of Si1-: XGex nanowires measured by optical pump-THz probe spectroscopy

Jung Min Bae, Woo Jung Lee, Seonghoon Jung, Jin Won Ma, Kwang Sik Jeong, Seung Hoon Oh, Seongsin M. Kim, Dongchan Suh, Woobin Song, Sunjung Kim, Jaehun Park, Mann-Ho Cho

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Slightly tapered Si1-xGex nanowires (NWs) (x = 0.29-0.84) were synthesized via a vapor-liquid-solid procedure using Au as a catalyst. We measured the optically excited carrier dynamics of Si1-xGex NWs as a function of Ge content using optical pump-THz probe spectroscopy. The measured -ΔT/T0 signals of Si1-xGex NWs were converted into conductivity in the THz region. We developed a fitting formula to apply to indirect semiconductors such as Si1-xGex, which explains the temporal population of photo-excited carriers in the band structure and the relationship between the trapping time and the defect states on an ultrafast time scale. From the fitting results, we extracted intra- and inter-valley transition times and trapping times of electrons and holes of Si1-xGex NWs as a function of Ge content. On the basis of theoretical reports, we suggest a physical model to interpret the trapping times related to the species of interface defect states located at the oxide/NW: substoichiometric oxide states of Si(Ge)0+,1+,2+, but not Si(Ge)3+, could function as defect states capturing photo-excited electrons or holes and could determine the different trapping times of electrons and holes depending on negatively or neutrally charged states.

Original languageEnglish
Pages (from-to)8015-8023
Number of pages9
JournalNanoscale
Volume9
Issue number23
DOIs
Publication statusPublished - 2017 Jun 21

Fingerprint

Nanowires
Pumps
Spectroscopy
Defects
Oxides
Electrons
Electron transitions
Band structure
Vapors
Semiconductor materials
Catalysts
Liquids

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Cite this

Bae, Jung Min ; Lee, Woo Jung ; Jung, Seonghoon ; Ma, Jin Won ; Jeong, Kwang Sik ; Oh, Seung Hoon ; Kim, Seongsin M. ; Suh, Dongchan ; Song, Woobin ; Kim, Sunjung ; Park, Jaehun ; Cho, Mann-Ho. / Ultrafast photocarrier dynamics related to defect states of Si1-: XGex nanowires measured by optical pump-THz probe spectroscopy. In: Nanoscale. 2017 ; Vol. 9, No. 23. pp. 8015-8023.
@article{8a81a27bda6f437894cda1f1ce3d441c,
title = "Ultrafast photocarrier dynamics related to defect states of Si1-: XGex nanowires measured by optical pump-THz probe spectroscopy",
abstract = "Slightly tapered Si1-xGex nanowires (NWs) (x = 0.29-0.84) were synthesized via a vapor-liquid-solid procedure using Au as a catalyst. We measured the optically excited carrier dynamics of Si1-xGex NWs as a function of Ge content using optical pump-THz probe spectroscopy. The measured -ΔT/T0 signals of Si1-xGex NWs were converted into conductivity in the THz region. We developed a fitting formula to apply to indirect semiconductors such as Si1-xGex, which explains the temporal population of photo-excited carriers in the band structure and the relationship between the trapping time and the defect states on an ultrafast time scale. From the fitting results, we extracted intra- and inter-valley transition times and trapping times of electrons and holes of Si1-xGex NWs as a function of Ge content. On the basis of theoretical reports, we suggest a physical model to interpret the trapping times related to the species of interface defect states located at the oxide/NW: substoichiometric oxide states of Si(Ge)0+,1+,2+, but not Si(Ge)3+, could function as defect states capturing photo-excited electrons or holes and could determine the different trapping times of electrons and holes depending on negatively or neutrally charged states.",
author = "Bae, {Jung Min} and Lee, {Woo Jung} and Seonghoon Jung and Ma, {Jin Won} and Jeong, {Kwang Sik} and Oh, {Seung Hoon} and Kim, {Seongsin M.} and Dongchan Suh and Woobin Song and Sunjung Kim and Jaehun Park and Mann-Ho Cho",
year = "2017",
month = "6",
day = "21",
doi = "10.1039/c7nr00761b",
language = "English",
volume = "9",
pages = "8015--8023",
journal = "Nanoscale",
issn = "2040-3364",
publisher = "Royal Society of Chemistry",
number = "23",

}

Bae, JM, Lee, WJ, Jung, S, Ma, JW, Jeong, KS, Oh, SH, Kim, SM, Suh, D, Song, W, Kim, S, Park, J & Cho, M-H 2017, 'Ultrafast photocarrier dynamics related to defect states of Si1-: XGex nanowires measured by optical pump-THz probe spectroscopy', Nanoscale, vol. 9, no. 23, pp. 8015-8023. https://doi.org/10.1039/c7nr00761b

Ultrafast photocarrier dynamics related to defect states of Si1-: XGex nanowires measured by optical pump-THz probe spectroscopy. / Bae, Jung Min; Lee, Woo Jung; Jung, Seonghoon; Ma, Jin Won; Jeong, Kwang Sik; Oh, Seung Hoon; Kim, Seongsin M.; Suh, Dongchan; Song, Woobin; Kim, Sunjung; Park, Jaehun; Cho, Mann-Ho.

In: Nanoscale, Vol. 9, No. 23, 21.06.2017, p. 8015-8023.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Ultrafast photocarrier dynamics related to defect states of Si1-: XGex nanowires measured by optical pump-THz probe spectroscopy

AU - Bae, Jung Min

AU - Lee, Woo Jung

AU - Jung, Seonghoon

AU - Ma, Jin Won

AU - Jeong, Kwang Sik

AU - Oh, Seung Hoon

AU - Kim, Seongsin M.

AU - Suh, Dongchan

AU - Song, Woobin

AU - Kim, Sunjung

AU - Park, Jaehun

AU - Cho, Mann-Ho

PY - 2017/6/21

Y1 - 2017/6/21

N2 - Slightly tapered Si1-xGex nanowires (NWs) (x = 0.29-0.84) were synthesized via a vapor-liquid-solid procedure using Au as a catalyst. We measured the optically excited carrier dynamics of Si1-xGex NWs as a function of Ge content using optical pump-THz probe spectroscopy. The measured -ΔT/T0 signals of Si1-xGex NWs were converted into conductivity in the THz region. We developed a fitting formula to apply to indirect semiconductors such as Si1-xGex, which explains the temporal population of photo-excited carriers in the band structure and the relationship between the trapping time and the defect states on an ultrafast time scale. From the fitting results, we extracted intra- and inter-valley transition times and trapping times of electrons and holes of Si1-xGex NWs as a function of Ge content. On the basis of theoretical reports, we suggest a physical model to interpret the trapping times related to the species of interface defect states located at the oxide/NW: substoichiometric oxide states of Si(Ge)0+,1+,2+, but not Si(Ge)3+, could function as defect states capturing photo-excited electrons or holes and could determine the different trapping times of electrons and holes depending on negatively or neutrally charged states.

AB - Slightly tapered Si1-xGex nanowires (NWs) (x = 0.29-0.84) were synthesized via a vapor-liquid-solid procedure using Au as a catalyst. We measured the optically excited carrier dynamics of Si1-xGex NWs as a function of Ge content using optical pump-THz probe spectroscopy. The measured -ΔT/T0 signals of Si1-xGex NWs were converted into conductivity in the THz region. We developed a fitting formula to apply to indirect semiconductors such as Si1-xGex, which explains the temporal population of photo-excited carriers in the band structure and the relationship between the trapping time and the defect states on an ultrafast time scale. From the fitting results, we extracted intra- and inter-valley transition times and trapping times of electrons and holes of Si1-xGex NWs as a function of Ge content. On the basis of theoretical reports, we suggest a physical model to interpret the trapping times related to the species of interface defect states located at the oxide/NW: substoichiometric oxide states of Si(Ge)0+,1+,2+, but not Si(Ge)3+, could function as defect states capturing photo-excited electrons or holes and could determine the different trapping times of electrons and holes depending on negatively or neutrally charged states.

UR - http://www.scopus.com/inward/record.url?scp=85021821108&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85021821108&partnerID=8YFLogxK

U2 - 10.1039/c7nr00761b

DO - 10.1039/c7nr00761b

M3 - Article

AN - SCOPUS:85021821108

VL - 9

SP - 8015

EP - 8023

JO - Nanoscale

JF - Nanoscale

SN - 2040-3364

IS - 23

ER -