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采用低温分子束外延法(LT-MBE)制备出Ga0.946Mn0.054As稀磁半导体(DMS)薄膜.通过X射线吸收谱(XAS)研究影响Ga0.946Mn0.054As薄膜性质的主要缺陷Mn间隙原子(MnI)和As反位原子(AsGa).实验结果表明,在较低生长温度(TS=200℃)下Ga0.946Mn0.054As晶格中缺陷分布以As反位原子(AsGa)为主;较高生长温度(TS>230℃)时样品中主要缺陷是Mn间隙(MnI)原子.同时,在较高低温退火温度(250℃)下可以使样品内部MnI向表面大量析出,减少反铁磁相,达到最高居里温度(130K).XAS结果还表明,退火可以使得表面的AsGa缺陷脱附,驱动周围的MnI原子填补AsGa缺陷留下的空位,提高MnGa原子浓度.
Ga0.946Mn0.054As diluted magnetic semiconductors (DMS) thin films were prepared by low temperature molecular beam epitaxy (LT-MBE). The main defects affecting the properties of Ga0.946Mn0.054As thin films were studied by X-ray absorption spectroscopy (XAS) MnI and AsGa.The experimental results show that the defect distribution of Ga0.946Mn0.054As lattice is mainly composed of As Inverted Atoms (AsGa) at the lower growth temperature (TS = 200 ℃) The main defect in the sample is Mn interstitial (MnI) atoms at the growth temperature (TS> 230 ℃), meanwhile MnI can be precipitated to the surface at higher annealing temperature (250 ℃) to reduce the antiferromagnetic phase, Reaches the highest Curie temperature (130K) .XAS results also show that annealing can make the AsGa surface desorption, drive the surrounding MnI atoms to fill vacancies left by AsGa defects and improve the concentration of MnGa atoms.