Photoemission study of chemisorption and Fermi-level pinning at K/GaAs(100) interface with synchrotron radiation
Photoemission study of chemisorption and Fermi-level pinning at K/GaAs(100) interface with synchrotron radiation
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DOI：
10.1016/j.apsusc.2004.12.012
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发表时间：
2005-08
影响因子：
6.7
通讯作者：
M. Sun;T. Zhao;C. Jia;P. Xu;E. Lu;C. Hsu;H. Ji
中科院分区：
文献类型：
--
作者：
M. Sun;T. Zhao;C. Jia;P. Xu;E. Lu;C. Hsu;H. Ji
用X射线光电子能谱(XPS)和同步辐射光电子能谱(SR-PES)研究了K在n-GaAs(100)表面的吸附。测量了清洁和K吸附的Ga3d和As3d核能级。K的吸附引发了K和As之间的化学反应，当K覆盖θ>；1ml时形成K-As反应物。K和Ga之间没有发生化学反应，但K原子与Ga原子发生了交换。从能带弯曲数据可知，肖特基势垒为0.70 eV。费米能级钉扎不是由缺陷能级引起的。这可能是由于表面Ga原子的悬垂键被K原子的外层电子填充，形成半填充的表面态。费米能级钉扎是由这种半填充表面态引起的。
The adsorption of K on the n-GaAs(100) surface was investigated by X-ray photoelectron spectroscopy (XPS) and synchrotron radiation photoemission spectroscopy (SR–PES). The Ga3d and As3d core level was measured for clean and K adsorbed GaAs(100) surface. The adsorption of K induced chemical reaction between K and As, and the K–As reactant formed when the K coverage θ>1ML. The chemical reaction between K and Ga did not occur, but Ga atoms were exchanged by K atoms. From the data of band bending, the Schottky barrier is 0.70eV. The Fermi-level pinning was not caused by defect levels. The probable reason is that the dangling bonds of surface Ga atoms were filled by the outer-shell electrons of K atoms, forming a half-filled surface state. The Fermi-level pinning was caused by this half-filled surface state.