Angle-resolved photoemission studies of GaAs(100) surfaces grown by molecular-beam epitaxy
Angle-resolved photoemission studies of GaAs(100) surfaces grown by molecular-beam epitaxy
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分子束外延生长的 GaAs(100) 表面的角分辨光发射研究
DOI：
10.1103/physrevb.27.4770
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发表时间：
1983
影响因子：
3.7
通讯作者：
D. Eastman
中科院分区：
文献类型：
--
作者：
T. Chiang;R. Ludeke;M. Aono;G. Landgren;F. Himpsel;D. Eastman
用角分辨光电子能谱技术研究了分子束外延生长的GaAs（100）表面。在12-70 eV的光子能量范围内研究了三种具有c（4× 4）、c（2× 8）和c（6× 4）重建表面结构的有序表面和无序As覆盖（1× 1）表面。在正常发射光谱中的所有主要尖锐峰被发现是从体价带的过渡，因此，由于表面状态的过渡是弱或宽。不同表面结构的体峰强度的变化与表面衍射效应有关。对于大于约20 eV的光子能量，主锥峰的转变从上部体价带到一个加宽和移位的自由电子类最终带被确定，并确定沿着[100]方向的上部价带的能量色散关系。表面umklapp过渡是相当强的，由于存在许多短的表面倒易晶格矢量。为了表征这些表面，进行了价带和芯能级的角积分光发射测量，并确定了这些表面的费米能级的位置。
Angle-resolved photoemission techniques were used to study GaAs (100) surfaces grown by molecular-beam epitaxy. Three well-ordered surfaces with the c (4× 4), c (2× 8), and c (6× 4) reconstructed surface structures and a disordered As-covered (1× 1) surface were investigated in the photon-energy range of 12-70 eV. All major sharp peaks in the normal-emission spectra were found to be transitions from bulk valence bands; therefore, transitions due to surface states were either weak or broad. The variations in bulk-peak intensities for different surface structures were related to surface diffraction effects. For photon energies greater than about 20 eV, primary-cone peaks for transitions from the upper bulk valence bands to a broadened and shifted free-electron-like final band were identified, and energy dispersion relations for the upper valence bands were determined along the [100] direction. Surface umklapp transitions were quite strong due to the presence of many short surface reciprocal-lattice vectors. To characterize these surfaces, angle-integrated photo-emission measurements of valence bands and core levels were made, and the positions of the Fermi level for these surfaces were determined.