Origin of High Mobility in Molybdenum-Doped Indium Oxide
Origin of High Mobility in Molybdenum-Doped Indium Oxide
复制标题
DOI：
10.1021/cm503896h
复制
发表时间：
2015-04-28
影响因子：
8.6
通讯作者：
Parkin, Ivan P.
中科院分区：
文献类型：
--
作者：
Bhachu, Davinder S.;Scanlon, David O.;Parkin, Ivan P.
用气溶胶辅助化学气相沉积(AACVD)方法制备的掺钼氧化铟(IMO)薄膜，其载流子迁移率较未掺杂薄膜有显著提高。通过使用混合哈密顿量、迁移率模型、X射线光电子能谱和X射线吸收光谱的密度泛函理论计算，研究了这种非常不寻常的行为的基础。与以往关于Mo是三电子施主的说法不同，结果表明，代位Mo在体禁带内捕获局域态的两个电子，因此Mo是一个简单的单电子施主。同时，在导带底部很少有Mo4d态与In5s态的杂化。这导致导电在一定程度上与施主分离，从而显著减少了电离杂质散射，增强了载流子迁移率。这与掺锡的In_2O_3相反，在In_2O_3中，导带极小值具有明显的Sn5s特征，导致规则的电离杂质散射。
Molybdenum-doped indium oxide (IMO) thin films prepared by aerosol-assisted chemical vapor deposition (AACVD) show significantly improved charge carrier Mobilities as compared to nominally undoped films prepared by the same technique. The basis for this very unusual behavior has been investigated by density functional theory calculations using a hybrid Hamiltonian, mobility modeling, X-ray photoemission, and X-ray absorption spectroscopies. In contrast to previous claims that Mo acts as a three-electron donor, it is shown that substitutional Mo traps two electrons in localized states falling within the bulk bandgap and thus Mo is a simple one-electron donor. At the same time, there is very little hybridization of Mo 4d states with In 5s states at the bottom of the conduction band. This results in conduction that is spatially separated to some degree from the donors, giving rise to significantly reduced ionized impurity scattering, enhancing the carrier mobility. This is in contrast to Sn-doped In2O3 where the conduction band minimum has significant Sn 5s character, resulting in regular ionized impurity scattering.