Ge基GaAs薄膜和InAs量子点MBE生长研究

Study on the growth of GaAs layer and InAs quantum dots on Ge substrate by molecular beam epitaxy

摘要: 采用分子束外延(MBE)法,在优化Ge衬底退火工艺的基础上,通过对比在(001)面偏<111>方向分别为0°、2°、4°和6°的Ge衬底上生长的GaAs薄膜,发现当Ge衬底的偏角为6°时有利于高质量GaAs薄膜的生长;通过改变迁移增强外延(MEE)的生长温度,发现在GaAs成核温度为375℃时,可在6°偏角的Ge衬底上获得质量最好的GaAs薄膜。通过摸索GaAs/Ge衬底上InAs量子点的生长工艺,实现了高效的InAs量子点光致发光,其性能接近GaAs衬底上直接生长的InAs量子点的水平。

Abstract: The 600-nm-thick GaAs epitaxial layers were grown on nominally 0o,2o,4o,and 6o–off misoriented（001） Ge substrates in molecular beam epitaxial（MBE） system,and it was found that the 6o offcut Ge substrates was proper for high quality GaAs epilayer growth.Moreover,by varying the temperature for the migration-enhanced epitaxial（MEE） process,the optimal nucleation temperature for GaAs epilayer was 375℃.With the optimization of growth parameters,InAs quantum dots with high photoluminescence efficiency were obtained on GaAs/Ge substrate,and the efficiency was comparable to that from InAs quantum grown on GaAs substrate.