TY - JOUR
T1 - Pump-probe STM light emission spectroscopy for detection of photo-induced semiconductor-metal phase transition of VO2
AU - Sakai, Joe
AU - Katano, Satoshi
AU - Kuwahara, Masashi
AU - Uehara, Yoichi
N1 - Funding Information:
This work was carried out under the Cooperative Research Project Program of the Research Institute of Electrical Communication, Tohoku University, Japan.
Publisher Copyright:
© 2017 IOP Publishing Ltd.
PY - 2017/8/31
Y1 - 2017/8/31
N2 - We attempted to observe pump-probe scanning tunneling microscopy (STM)-light emission (LE) from a VO2 thin film grown on a rutile TiO2(0 0 1) substrate, with an Ag tip fixed over a semiconducting domain. Laser pulses from a Ti:sapphire laser (wavelength 920 nm; pulse width less than 1.5 ps) irradiated the tip-sample gap as pump and probe light sources. With a photon energy of 2.7 eV, suggesting phase transition from semiconducting monoclinic (M) to metallic rutile (R) phases in relation to the electronic band structure, faint LE was observed roughly 30 ps after the irradiation of the pump pulse, followed by retention for roughly 20 ps. The incident energy fluence of the pump pulse at the gap was five orders of magnitude lower than the threshold value for reported photo-induced M-R phase transition. The mechanism that makes it possible to reduce the threshold fluence is discussed.
AB - We attempted to observe pump-probe scanning tunneling microscopy (STM)-light emission (LE) from a VO2 thin film grown on a rutile TiO2(0 0 1) substrate, with an Ag tip fixed over a semiconducting domain. Laser pulses from a Ti:sapphire laser (wavelength 920 nm; pulse width less than 1.5 ps) irradiated the tip-sample gap as pump and probe light sources. With a photon energy of 2.7 eV, suggesting phase transition from semiconducting monoclinic (M) to metallic rutile (R) phases in relation to the electronic band structure, faint LE was observed roughly 30 ps after the irradiation of the pump pulse, followed by retention for roughly 20 ps. The incident energy fluence of the pump pulse at the gap was five orders of magnitude lower than the threshold value for reported photo-induced M-R phase transition. The mechanism that makes it possible to reduce the threshold fluence is discussed.
KW - VO
KW - light emission
KW - pulsed laser deposition
KW - scanning tunneling microscopy
KW - thin films
KW - time-resolved spectroscopy
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U2 - 10.1088/1361-648X/aa7f93
DO - 10.1088/1361-648X/aa7f93
M3 - Article
C2 - 28703712
AN - SCOPUS:85029538356
VL - 29
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
SN - 0953-8984
IS - 40
M1 - 405001
ER -