Fabrication of 3D Photospinic Crystals

为了制备和研究自旋控制光子晶体，制备了高纵横比三角形阵列的柱状结构。利用电子束光刻技术在砷化镓表面上制作了三角形阵列的点掩模。然后用BCl_3流蚀刻图案衬底。样品的SEM图像显示柱状结构，纵横比为6.6 ~ 10。为了形成三维光子晶体，这些结构被SiO_2用TEOS-PECVD埋藏。作为光子晶体的另一种制备技术，用NH_4OH电解液在以下条件下对GaAs晶片进行阳极氧化；外加磁场垂直或平行于GaAs（001）表面。作为测试，我们成功地形成了高阶蜂窝空心阵列。此外，MBE在这些蜂窝空腔上生长InAs导致了InAs点位置的控制。考虑到自旋相关现象，MBE在带有v型凹槽的GaAs衬底上生长了MnAs/GaAs异质结构。样品的磁滞测量结果显示，样品具有双步磁滞特征。

In order to fabricate and investigate spin-controlled photonic crystals, the pillar structures of triangular arrays with high aspect ratio were fabricated. The dot mask of triangular array was patterned on GaAs surfaces by electron beam lithograph. The patterned substrate was next etched with BCl_3 flow. SEM images of the samples showed pillar structures with the aspect ratio of 6.6〜10. In orde to form 3D photonic crystals, these structures were buried by SiO_2 using TEOS-PECVD.As another fabrication technique of photonic crystals, GaAs wafers were anodized with NH_4OH electrolyte under the following conditons ; the external magnetic field was applied in perpendicular or parallel to the GaAs (001) surface. As a resit, we succeeded in forming high-odered honeycomb hollow arrays. Moreover, MBE growth of InAs on there honeycomb hollows led to controling the site of InAs dotsConcerning spin-related phenomena, MnAs/GaAs heterostructures were grown on GaAs substrates with V-grooves by MBE. VSM measurements of these samples showed that double-step magnetic hysteresis features were observed.