InAs dots including Mn atoms fabricated by MOMBE

InAs quantum-dot structures including Mn atoms are fabricated on GaAs substrate by metalorganic molecular beam epitaxy (MOMBE) method. Mn atoms are first deposited on GaAs substrate and InAs dots are formed at the Mn atoms nuclei (probably in the form of MnAs) using TMIn (trimethylindium) and TDMAAs (trisdimethylaminoarsenic) sources. Large-size InAs dots including Mn atoms as well as Stranski–Krastanov (S–K) mode-grown small-size InAs dots are formed on the surface. The small-size InAs dots are subsequently removed by in situ etching with bisdimethylaminoarsenicchloride (BDMAAsCl), and only InAs dots including Mn atoms are left. Growth temperature dependence of the formed InAs dots supports this process. These are confirmed by atomic force microscopy (AFM) and magnetic force microscopy (MFM) measurements. The magnetization properties are measured with a superconducting quantum interference device (SQUID) magnetometor and it is found that the easy axis of magnetization for InAs dots including Mn atoms is perpendicular to the GaAs surface.