Conducting and insulating LaAlO3/SrTiO3 interfaces: A comparative surface photovoltage investigation
Conducting and insulating LaAlO3/SrTiO3 interfaces: A comparative surface photovoltage investigation
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DOI：
10.1063/1.4858376
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发表时间：
2013-12-28
影响因子：
3.2
通讯作者：
Eng, L. M.
中科院分区：
文献类型：
--
作者：
Beyreuther, E.;Paparo, D.;Eng, L. M.
表面光电压谱（SPY）是一种分析宽带隙半导体（异质）结构表面和界面电子缺陷态能量分布的通用方法，本文应用SPY对生长在TiO_2和SrO封端的SrTiO_3上的5个晶胞厚的LaAl_3薄膜异质结构进行了比较研究。这两个界面表现出显著不同的特性，第一个界面是导电的，而第二个界面是绝缘的。我们目前的SPY调查揭示了清晰可辨的界面缺陷态分布的两种配置时，在一个经典的半导体能带结构的框架内解释。此外，裸SrTiO 3晶体与TiO 2或混合SrO/TiO，终端显示类似的SPY光谱和瞬态做LaAlO 3覆盖的样品与各自的终止的SrTiO 3基板，这是根据一些最近的工作，强调SrTiO 3的决定性作用和次要作用的LaAlO 3相对于电子界面性能。(C)2013 AIP Publishing LLC.
Surface photovoltagc (SPY) spectroscopy, which is a versatile method to analyze the energetic distribution of electronic defect states at surfaces and interfaces of wide-bandgap semiconductor (hetero-)structures, is applied to comparatively investigate heterostructures made of 5-unit-cell-thick LaAlO3 films grown either on TiO2- or on SrO-terminated SrTiO3, As shown in a number of experimental and theoretical investigations in the past, these two interfaces exhibit dramatically different properties with the first being conducting and the second insulating. Our present SPY investigation reveals clearly distinguishable interface defect state distributions for both configurations when interpreted within the framework of a classical semiconductor band scheme. Furthermore, bare SrTiO3 crystals with TiO2 or mixed SrO/TiO, terminations show similar SPY spectra and transients as do LaAlO3-covered samples with the respective termination of the SrTiO3 substrate, This is in accordance with a number of recent works that stress the decisive role of SrTiO3 and the minor role of LaAlO3 with respect to the electronic interface properties. (C) 2013 AIP Publishing LLC.