【摘要】 本文介绍利用一种将单晶锭条两端固定,中间可以重熔以建立悬浮熔区的反应容器,在回地卫星的微重力环境下用45分钟从熔区两端相向生长出中部直径为1cm,长度分别为10mm和7mm的两块火炬头状砷化镓单晶.对地面生长和空间生长7mm长单晶用KOH溶液为电解液的阳极腐蚀法显示,结果表明:在地面生长的籽晶部位观察到了由重力驱动对流引起温度涨落而造成的密排杂质条纹,在与籽晶相邻接的空间生长单晶部位未观察到这种类型的杂质条纹.同时观察到太空生长单晶边缘附近存在杂质条纹以及在太空单晶末端附近边缘出现胞状结构,它们可能是因降温速率快过冷所致.经熔融KOH腐蚀显示,在地面单晶和10mm长空间单晶交界面出现密排位错,靠近交界面的太空生长单晶位错密度较低,随着晶体生长位错密度逐渐增高,太空生长单晶边缘附近位错密度高于中心区域.更多还原

【Abstract】 In order to prepare high homogeneity GaAs crystal, the authors have grown GaAs singlecrystal from melt in space.In space the floating melt zone was formed in the middle ofingot,then the single crystals were grown face to face from two ends of the melt when the tem-perature decreased slowly.The two crystals grown in space are in the shape of torch head ofdiameter 1 cm, and their lengthes are 1 cm and 0.7 cm respectively.The electric power canbe supplied only for 90 minutes due to certain reasons.The temperature dropped rapidlyfrom the melt and thus resulted in the break of the melting zone.The middle melting zonewas drawn to the space-grown single crystal of length 0.7 cm and formed polycrystal coveringits surface. After the anodic etching of the crystal cross section cut along the axis of the ingot, usingan electrolyte of aqueous potassium hydroxide (KOH), the densely aligned parallel striationscaused by thermal convection appear on the surface of seed crystal, not on the space-growncrystal.The impurity striations are observed near some surface regions of space-grown crystaland cellar structures appear near the end of it.These may be caused by supercooling due tothe relatively rapid cooling process.更多还原