Fabrication, characterization arid application of GaAs hole arrays with high aspect ratio

研究了磁场对GaAs阳极氧化过程中结构性质的影响，以期深入了解在GaAs表面形成有序孔阵列的过程。研究发现，磁场诱导的洛伦兹力对蜂窝孔阵的形成有很大影响。在磁场平行于表面的情况下，当磁场增加到1.5T时，蜂窝孔的规整性增加。蜂窝孔的尺寸也随着磁场的增大而增大。然后，以阳极多孔氧化铝为起始结构，通过复制工艺制备出具有高有序孔型的GaAs孔阵列。在优化条件下制得的多孔氧化铝平均直径为26 nm，密度为4×10~(-1)cm~(-2)。然后用BCl3在干法刻蚀系统中对覆盖有多孔氧化铝的GaAs衬底进行刻蚀。去除多孔氧化铝后，在GaAs衬底上形成了高序度的孔阵列。孔阵列的平均直径为23 nm，孔阵列密度为4×10；lt；10&gt；cm2。最后，采用分子束外延技术在图案化的GaAs衬底上生长了InAs量子点。发现一些InAs点选择性地生长在孔阵列的底部。InAs量子点的平均直径为15 nm。

The effect of a magnetic field on the structural properties during anodization of GaAs substrates was investigated to gain insights into formation of ordered hole arrays on GaAs surfaces. It was found that Lorentz force induced by a magnetic field considerably affects formation of honeycomb hole arrays. In the case of the anodization with a magnetic field parallel to the surface, regularity of honeycomb holes was increased with increasing the magnetic field up to 1.5T. The size of honeycomb holes was also increased with increasing the magnetic field.The GaAs hole array with high-odered hole configuration was next prepared by a replication process using anodic porous alumina as a starting structure. The average diameter of porous alimina was 26 nm, and the density of porous alumina was 4×10^<10>cm^2 under an optimized condition. GaAs substrates covered by the porous alumia was then etched using BCl_3 in a dry-etching system. After removing porous alumina, high-odered hole arrays were formed on GaAs substrates. The average diameter of hole array was 23 nm, and the density of hole array was 4×10^<10>cm^2.InAs quantum dots were finally grown by molecular-beam epitaxy on the patterned GaAs substrates. It was found that some of InAs dots were selectively grown at the bottom of hole arrays. The average diameter of InAs quantum dots was 15 nm.