覆盖层
工作职能
异质结
带材弯曲
费米能级
化学
光电发射光谱学
电子
原子物理学
凝聚态物理
分析化学(期刊)
X射线光电子能谱
图层(电子)
物理
核磁共振
物理化学
有机化学
量子力学
色谱法
作者
P. Zürcher,R. S. Bauer
出处
期刊:Journal of vacuum science & technology
[American Vacuum Society]
日期:1983-04-01
卷期号:1 (2): 695-700
被引量:56
摘要
Synchrotron radiation-excited soft x-ray photoemission is used to study the heterojunction formation of GaAs on Ge(110) by examining 3d-core levels, the valence band (VB), and the secondary electron distribution cutoff in a photoemission spectrum. Arsenic saturation of the Ge(110) surface prior to MBE growth of GaAs causes a work function increase of 0.26±0.045 eV and a decrease in Ge valence-band maximum (VBM) from the Fermi level by 0.96±0.09 eV. The increase in work function can be explained by the formation of a GeAsx layer. The large VBM decrease is partly due to a band bending of 0.61±0.03 eV and a chemisorption-induced charge transfer reaction. Using two different photoemission methods, the VB discontinuity at the interface is determined to be 0.23±0.08 and 0.26±0.07 eV. This value is different from the one determined for the inverse heterojunction where Ge is deposited on top of GaAs(110) at the same epitaxial growth temperature of 320 °C. The difference in electron affinity between the clean Ge(110) substrate and the GaAs(110) overlayer is Δχ=−0.01±0.08 eV. Therefore, Anderson’s electron affinity rule does not explain the measured VB discontinuity.
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