物理学报2016，Vol.65Issue(16)：167301-1-167301-6,6.DOI:10.7498/aps.65.167301
三维a-IGZO薄膜中的电子-电子散射∗
Electron-electron scattering in three-dimensional amorphous IGZO films
摘要
Abstract
Electron dephasing process is important and interesting in disordered conductors. In general three-dimensional (3D) disordered metals, the electron-electron (e-e) scattering is negligibly weak compared with the electron-phonon (e-ph) scattering. Thus, the theoretical prediction concerning the e-e scattering rate 1/τee as a function of temperature T in 3D disordered conductor has not been fully tested so far, though it was proposed four decades ago. In the frame of free-electron-like model, the e-ph relaxation rate 1/τep is proportional to carrier concentration n, while the small- and large-energy-transfer e-e scattering rate obey the laws 1/τSee ∝ n−4/3 and 1/τLee ∝ n−2/3, respectively. In other words, e-e scattering may dominate the dephasing processes in 3D disordered metals with sufficient low carrier concentrations. In the present work, we systematically investigate the electronic transport properties of amorphous indium gallium zinc oxide (a-IGZO) prepared by the radio frequency sputtering method. The carrier concentrations of the highly degenerate IGZO films are all ∼5 × 1019 cm−3, which are 3–4 orders of magnitude lower than those of typical metals. Our thick films (∼800 nm) are 3D systems with respect to weak-localization (WL) effect and e-e scattering. X-ray diffraction patterns of the films indicate that our films are all amorphous. For each film, the resistivity increases with the increase of the temperature in the high temperature region (T >200 K) and the carrier concentration is almost invariable in the whole measured temperature range. This indicates that the films possess metal-like transport properties. By comparing the low-field magnetoconductivity versus magnetic field data σ(B) with that from the 3D WL theory, we extract the electron dephasing rate 1/τϕat different temperatures in the low temperature region. It is found that 1/τϕvaries linearly with T 3/2 for each film. The T 3/2 behavior of 1/τϕ can be quantitatively described by the 3D small-energy-transfer e-e scattering theory. The e-ph scattering rate 1/τep and large-energy-transfer e-e scattering rate 1/τLee are negligibly weak in this low-carrier-concentration conductor. Thus, we can observe the T 3/2 behavior of 1/τϕ.关键词
电子散射/弱局域效应/电子输运性质Key words
electron scattering mechanisms/weak-localization effect/electron transport properties引用本文复制引用
张辉,杨洋,李志青..三维a-IGZO薄膜中的电子-电子散射∗[J].物理学报,2016,65(16):167301-1-167301-6,6.基金项目
国家自然科学基金(批准号:11174216)和高等学校博士学科点专项科研基金(批准号:20120032110065)资助的课题.* Project supported by the National Natural Science Foundation of China (Grant No.11174216) and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20120032110065) （批准号:11174216）
