Holes doping effect on the phase transition of VO2 film via surface adsorption of F(4)TCNQ molecules
Holes doping effect on the phase transition of VO2 film via surface adsorption of F(4)TCNQ molecules
复制标题
F(4)TCNQ分子表面吸附空穴掺杂对VO2薄膜相变的影响
DOI：
10.1016/j.apsusc.2018.03.228
复制
发表时间：
2018
影响因子：
6.7
通讯作者：
Xu Faqiang
中科院分区：
文献类型：
--
作者：
Wang Kai;Zhang Wenhua;Liu Lingyun;Guo Panpan;Yao Yi;Wang Chia-Hsin;Zou Chongwen;Yang Yaw-Wen;Zhang Guobin;Xu Faqiang
通过四氟四氰基对醌二甲烷 (F4TCNQ) 分子吸附诱导的表面电荷转移，研究了空穴掺杂对 VO2 薄膜金属-绝缘体转变 (MIT) 行为的影响。与原始 VO2 薄膜的 MIT 工艺相比，F4TCNQ 覆盖的 VO2 样品的临界温度降低了约 4°C。基于同步辐射光子电子光谱（SRPES）、X射线吸收近边结构（XANES）光谱和变温拉曼光谱等详细实验，深入研究了MIT的抑制机制。结果表明，由于有效的空穴掺杂，F4TCNQ 覆盖的 VO2 样品的电子结构发生了明显的变化。此外，掺杂空穴还会改变V 3d轨道占据并削弱电子-电子相关性，降低晶体稳定能。上述两种效应都有利于触发MIT提前发生，导致临界温度降低。
The holes doping effect on the metal–insulator transition (MIT) behavior of VO2film is investigated via the tetrafluorotetracyanoquinodimethane (F4TCNQ) molecules adsorption induced surface charge transfer. Comparing with the MIT process of pristine VO2film, a critical temperature decrease of about 4 °C for the F4TCNQ covered VO2sample is observed. The MIT depression mechanism is deeply investigated based on detailed experiments including synchrotron radiation photon electronic spectroscopy (SRPES), X-ray absorption near-edge structure (XANES) spectroscopy and variable temperature Raman spectroscopy. Results indicate that the electronic structures of F4TCNQ covered VO2sample are changed clearly due to the effective holes doping. In addition, the doped holes also change the V 3d orbital occupancy and weaken the electron–electron correlation as well, lowering the crystalline stability energy. Both of the above effects are in favor of triggering the earlier occurrence of MIT, resulting in the decrease of critical temperature.