Research in the electronic structure of MnSi/Si interface by soft X-ray emission spectroscopy and inverse resonant photoelectron spectroscopy

电子器件的最新发展已经在诸如MnSi/Si层的界面领域中取得。为了研究MnSi/Si界面的电子性质，我们采用了软X射线发射谱和共振逆光电子能谱。K_β发射谱是由Si的3 p价带到Si的2 p芯空穴跃迁引起的。用电子激发法和改变X射线从样品表面的出射角θ t进行测量。当θ t = 2 °时，SiK β谱代表体Si的3 p价带结构。在θ t = 0.5 °处，即X射线的全反射角θ c（临界角），Si-K β谱显示了表面氧化Si的电子结构，即SiO_2。当θ t介于上述两个角度之间时，当θ t = 1 ° ~ 1.5 °时，K_β谱显示SiO_2/Si界面的电子结构，价带Si 3 p峰系统地向低能移动。这种峰移可以用半导体异质结的能带偏移模型来理解。接下来，我们通过改变起飞角θ_t，观察了MnSi/Si系统的Si-K_β谱和Mn L_α谱。

Recent development of electronic devices has been made in the field of interface such as MnSi/Si layer. In order to study the electronic properties of MnSi/Si interface, we have noticed the soft X-ray emission spectroscopy and the resonant inverse photoelectron spectroscopy.At first, we have measured the Si-K_β emission spectra of Si single crystal. The K_β emission spectrum is induced by the Si 3p valence band to the Si 2p core hole transition. Measurements were carried out by electron excitation method and by changing the X-ray take-off angle (θ_t) from sample surface. When at θ_t = 2 °, SiK_β spectrum represents the Si 3p valence band structure of bulk Si. On the other hand, at θ_t = 0.5 °, which corresponds to the total reflection angle θ_c (critical angle) of X-rays, the Si-K_β spectrum shows the electronic structure of surface oxidized Si, i.e. SiO_2. Where θ_t is between above angles, at θ_t = 1 ° and, 1.5 °, the K_β spectra show the electronic structures of SiO_2/Si interface and the valence band Si3p peak shifts systematically to the lower energy. This peak shift may be understood by the band offset model of semiconductor heterojunction.Next, we observed the Si-K_β spectra and the Mn L_α spectra from MnSi/Si system by changing the take-off angel θ_t.