Insertion Effect of the Monolayr of Column II Elements at GaAs/Si Interface

我们提出电荷平衡异质外延，其中GaAs/Si界面中和插入一个单层的第II列元素在GaAs/Si界面的Ga原子的地方。我们用Be原子构建了这种结构，用高能电子衍射（RHEED）、紫外光电子能谱（UPS）和X射线光电子能谱（XPS）研究了在这种电荷平衡结构上GaAs分子束外延生长的初始阶段，在经紫外光处理的Si（111）衬底上，在900 ℃加热后，获得了清晰的（7 × 7）RHEED图样。在450 ℃下同时沉积Be和As时，Si（1x1）-As表面上的As孤对态逐渐减少。在此电荷平衡结构上于450 ℃生长单层GaAs后，获得了类GaAs的UPS谱。此外，宽条纹（1 × 1）的RHEED图案保持，直到几个单层GaAs沉积。Si的2p XPS测量也证实了界面处核电荷的积累被消除，表明电荷平衡结构中和了GaAs/Si界面，GaAs生长模式以Sttranski-Krastanow模式进行。

We propose charge-balance heteroepitaxy, where the GaAs/Si interface is neutralized by inserting one monolayr of column II elements in place of the Ga atoms at GaAs/Si interface. We have constructed this structure using Be atoms, and have investigated the initial stages of GaAs molecular beam epitaxy growth on this charg-balanced structure by high-energy electron diffraction (RHEEED), and ultraviolet and X-ray photoemission spectroscopy (UPS,XPS).After Si (111) substrates which are treated under UV light, are heated at 900ﾟC,the sharp (7x7) RHEED pattern is obtained. As lone-pair states on Si (1x1) -As surfaces gradually decreases as depositing both Be and As at 450ﾟC.After one onolayr deposition of BeAs, this peak completely disappears. After one monolayr GaAs growth on this charge-balanced structure at 450ﾟC,GaAs-like UPS spectrum is obtained. Furthermore, a broad streaked (1x1) RHEED pattern remains till several monolayr GaAs deposition. The Si 2p XPS measurements also support that accumulation of nuclear charge at the interface is extinguished.These measurements reveal that the charge-balanced structure neutralizeds the GaAs/Si interface, and the GaAs growth mode proceeds in a Stranski-Krastanow mode.