세종대학교 두드림 비교과통합관리시스템

‧제목 Study of electronic structure of  VO2throughK-andL-edgeresonancephenomena

‧연사 Canadian Light Source, Senior scientist      김창용

‧일시 2019년 05월 14일 (화요일) 오후 5시

‧장소 영실관 601호

초 록

The first order metal-insulator (M-I) transition observed in VO₂ at temperature of 341 K accompanies crystallographic transition from monoclinic (low temperature insulator) to tetragonal rutile (high temperature metal). As temperature decreases vanadiums dimerize and twist along c-axis (<001> direction) of high temperature rutile structure and induce structural transition to low temperature monoclinic.

Diffractive anomalous near edge structure (DANES) measurement is combination of X-ray diffraction and absorption spectroscopy, which can provide element-, phase, and crystallographic site-specific electronic structure. Vanadium K-edge DANES measurement from monoclinic phase above the M-I transition temperature confirmed existence of monoclinic metal phase (MMP). Implication of the observed MMP will be discussed in conjunction with carrier doping through surrounding metallic phase.

 Vanadium 2p-3d resonance photoemissions from VO₂ thin film grown on n- and p-type silicon substrates have been used to study photo-carrier injection from silicon substrates at a low temperature. Photo-carrier injection modifies V3d - O 2p hybridization and surprisingly vanadium 2p_3/2- 2p_1/2 intermixing as well. Possibility of intermixing of transition metal 2p state through hybridization with oxygen ligand will be discussed

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