TiO2-SnO2:F interfacial electronic structure investigated by soft x-ray absorption spectroscopy
TiO2-SnO2:F interfacial electronic structure investigated by soft x-ray absorption spectroscopy
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DOI：
10.1103/physrevb.85.125109
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发表时间：
2012-03-09
影响因子：
3.7
通讯作者：
Mao, Samuel S.
中科院分区：
文献类型：
--
作者：
Kronawitter, Coleman X.;Kapilashrami, Mukes;Mao, Samuel S.
利用同步辐射软X射线吸收光谱研究了二氧化钛（TiO 2）-掺氟二氧化锡（SnO 2：F）界面的电子结构。这些测量探测了位置选择的未占据态密度，并反映了早期过渡金属氧化物（d（0））半导体和后过渡金属氧化物（d（10））简并半导体之间的相互作用。通过与金红石型和金红石型TiO_2、SnO_2：F、ZnO-SnO_2：F和CdO-SnO_2：F界面的光谱对比，确定了TiO_2-SnO_2：F界面的独特电子结构。氧的1 s吸收光谱，这涉及到的O 2 p偏态密度的导带，表明该接口是与减少在Ti d-O p轨道杂化和改变的TiO 2晶体场。这些观察结果与测得的钛2 p吸收光谱一致，这另外提供了在界面TiO 2中的阳离子位点周围的长程有序畸变的证据。TiO 2-SnO 2：F界面是许多光电器件的功能组件，可能最值得注意的是在太阳能电池架构的阳极结构中。在非平衡条件下，例如在操作太阳能电池中发现的那些条件下，界面电子结构通过改变例如准费米能级电子和透明电极处的电势分布来直接影响性能。
The electronic structure of the titanium dioxide (TiO2)-fluorine-doped tin dioxide (SnO2:F) interface is investigated by soft x-ray absorption spectroscopy using synchrotron radiation. The measurements probe the site-and symmetry-selected unoccupied density of states and reflect the interaction between an early transition-metal-oxide (d(0)) semiconductor and a post-transition-metal-oxide (d(10)) degenerate semiconductor. The distinct interfacial electronic structure of TiO2-SnO2:F is established by contrasting spectra with those for anatase and rutile TiO2, SnO2: F, and ZnO-SnO2:F and CdO-SnO2:F interfaces. Oxygen 1s absorption spectra, which relate to the O 2p partial density of states of the conduction band, indicate that the interface is associated with a reduction in Ti d-O p orbital hybridization and an alteration of the TiO2 crystal field. These observations are consistent with measured titanium 2p absorption spectra, which in addition provide evidence for distortion of long-range order around the cation site in the interfacial TiO2. The TiO2-SnO2:F interface is a functional component of a number of optoelectronic devices, perhaps most notably within the anode structure of solar cell architectures. In nonequilibrium conditions, such as those found in operating solar cells, interfacial electronic structure directly influences performance by modifying, for instance, the quasi-Fermi level electrons and the potential distribution at the transparent electrode.