Interface Properties of Dielectric Oxides
Interface Properties of Dielectric Oxides
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DOI：
10.1111/jace.14074
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发表时间：
2016-02-01
影响因子：
3.9
通讯作者：
Klein, Andreas
中科院分区：
文献类型：
--
作者：
Klein, Andreas
介绍并讨论了利用光电子能谱法获得的介质氧化物界面的化学和电子性质。界面制备包括金属在电介质上的沉积，反之亦然，以及沉积后处理的效果。大多数界面不是突然的，要么是在金属沉积过程中氧化表面的还原发生，要么是金属基底的氧化由氧化沉积引起。这些界面上的肖特基势垒高度受到界面化学的强烈影响。由于缺陷的形成，反应界面表现出很强的费米能级钉住。通过沉积金属氧化物电极获得的非反应性界面表现出未固定的肖特基-莫特类势垒形成。因此，通过合适的电极材料和加工，势垒高度可以修改为1 eV以上。沉积后氧化和还原处理和铁电极化可以导致势垒高度的类似变化。对介电氧化物界面的研究揭示了价带最大值和导带最小值能量的依赖性。由于带对准的传递性，这些可以在绝对能量尺度上排列。电介质氧化物中的费米能级位置的范围，也可以从光电子能谱中得到，但受内在缺陷形成的限制，当氧化物在光发射实验确定的能量尺度上排列时，是相当的。因此，能带排列表明材料是否可以通过供体或受体掺杂制成n型或p型。氧化物中的费米能级范围也与氧化物/金属界面处的费米能级范围相对应。
Chemical and electronic properties of dielectric oxide interfaces as obtained using photoelectron spectroscopy are presented and discussed. Interface preparation includes the deposition of metals onto dielectrics and vice versa as well as the effect of postdeposition treatments. Most interfaces are not abrupt as either reduction in the oxide surface occurs during metal deposition or oxidation of the metal substrate is induced by oxide deposition. The Schottky barrier heights at these interfaces are strongly affected by the interface chemistry. Reactive interfaces exhibit a strong Fermi level pinning due to defect formation. Nonreactive interfaces, which are obtained by depositing metallic oxide electrodes, exhibit an unpinned Schottky-Mott-like barrier formation. Barrier heights can therefore be modified by more than 1 eV with suitable electrode material and processing. Postdeposition oxidation and reduction treatments and ferroelectric polarization can lead to comparable changes of barrier height. Interface studies between dielectric oxides reveal the dependence of valence band maximum and conduction band minimum energies. Due to transitivity of band alignment, these can be arranged on an absolute energy scale. The range of Fermi level positions in dielectric oxides, which can also be obtained from photoelectron spectroscopy and which is limited by intrinsic defect formation, is comparable when the oxides aligned on the energy scale determined by the photoemission experiments. The band alignment therefore indicates if a material can be made n-type or p-type by donor or acceptor doping. The range of Fermi levels in the oxides corresponds also with the range of the Fermi levels at oxide/metal interfaces.