Study On Properties Of GaAs-Based Diluted Magnetic Semiconductors

New hybrid devices coupling magnetic and conduction properties can be fabricated by different ways to control and to manipulate both the charge and the spin of carriers. Due to the wide application of GaAs material in high speed electronic devices and photoelectric devices, the GaAs base diluted magnetic semiconductor is paid more attentions. Ferromagnetic MnAs and MnGa in GaAs with the Curie temperature above 300 K, by ion implantation with subsequent annealing, have attracted a great deal of interest because of their possible applications to the semiconductor spintronics.In this thesis, the effect of annealing on the MnAs and MnGa clusters in GaAs was studied. Mn ion was implanted into GaAs substrates ,and MnAs or MnGa phase which show ferromagnetism were formed by annealing at 650℃-900℃. In order to research effect of annealing on the MnAs and MnGa clusters in GaAs, Atom Force Microscope(AFM), Magnetic Force Microscope (MFM), Secondary Ion Mass Spectrometry(SIMS) were employed. It was found that size distribution and densities of MnAs and MnGa clusters was affected by annealing conditions. The implanted samples were annealed at temperatures 650℃and 850℃,in the other case a pre-anneal was performed at 500℃,after that the samples were annealed at 850℃. The measurements showed that in the case of 650℃annealing, MnAs and MnGa clusters was small and dense .The AFM measurements show that the crystal lattice structure will be restored after annealing, and the crystal lattice structure of sample after two-step annealing was better than the sample after single annealing. The distributions of Mn in annealed samples were measured by Secondary Ion Mass Spectrometry, it is showed that the temperature of annealing has great affection on the distribution of Mn in sample.