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

我们提出了电荷平衡异质外延，通过在界面上插入一个单层的第II列元素来代替Ga原子来中和GaAs/Si界面。我们利用Be原子构建了这种结构，并用高能电子衍射、紫外光和X射线光电子能谱研究了在这种电荷平衡结构上生长的分子束外延的初始阶段。经过紫外光处理的Si(111)衬底在900ﾟC下加热，得到了尖锐的(7×7)RHEED图形。在450ﾟC沉积Be和As时，Si(1x1)-As表面的孤对态逐渐减少。沉积一次BeAs后，这一峰完全消失。在这种电荷平衡结构上生长单层GaAs后，在450C的ﾟ温度下，获得了类GaAsUPS谱。此外，宽条纹(1x1)的RHEED图案一直保持到几个单层的GaAs膜。Si2p XPS测量也证实了界面上的核电荷积累被消除，这些测量结果表明电荷平衡结构中和了GaAs/Si界面，并且GaAs的生长模式以STranski-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.