【摘要】 用分子束外延方法在BaF2(111)衬底上生长了PbTe单晶薄膜,原子力显微镜(AFM)的表面形貌表征显示PbTe表面具有单原子层的平整性,并观察到由螺位错形成的螺旋台阶面。高分辨X射线衍射(HRXRD)测量得到PbTe(111)衍射峰的线宽<100 arc sec,表明薄膜具有优良的晶体结构特性。然后将样品暴露于大气环境中3个月后,用X射线光电子谱(XPS)分析了PbTe表面的氧化机理,发现PbTe表面氧化形成了PbO和TeO2,接着将样品在超高真空中加温,同时测量样品表面的Pb、Te、O元素价态、束缚能、含量等参量随温度的变化,发现在温度达到475℃时PbTe样品表面的氧化层已除去,获得了较干净的PbTe表面,为PbTe光电器件工艺提供了实验依据。更多还原

【Abstract】 PbTe films were grown by molecular beam epitaxy(MBE) on BaF2(111) substrates.Surface microstructures and surface oxidation were characterized with high resolution X-ray diffraction(HRXRD),atomic force microscopy(AFM),low energy electron spectroscopy(LEED) and X-ray photoelectron spectroscopy(XPS).Helical steps were clearly observed on the fairly smooth,compact PbTe surfaces.After exposure in air for three months,thin layers of PbO and TeO2 were found to exist on top of the films.We found that annealing at a temperature of 475 ℃ in ultra high vacuum completely removes the oxidized layers from the PbTe film surfaces.Possible mechanisms were also tentatively discussed.更多还原