Ashraf T, Gusenbauer C, Stangl J, Hesser G, Koch R
National Institute of Lasers and Optronics, Islamabad, Pakistan.
J Phys Condens Matter. 2015 Jan 28;27(3):036001. doi: 10.1088/0953-8984/27/3/036001. Epub 2014 Dec 24.
We studied epitaxy, growth, structure and morphology of thin Fe(0 0 1) films on the As-rich GaAs(0 0 1)-c(4 × 4) surface, deposited by molecular beam epitaxy at growth temperatures between room temperature and 250° C. Electron and x-ray diffraction (XRD) techniques evidence epitaxial growth with Fe(0 0 1)[1 0 0] ∥ GaAs(0 0 1)[1 0 0]. The residual strain derived from the XRD results is consistent with recent stress measurements. Cross-sectional transmission electron microscopy reveals an abrupt interface for room-temperature films and the formation of a ∼10 nm thick crystalline Fe-Ga-As intermediate layer at 250° C. The dependence of the surface morphology on growth temperature and annealing evidences a kinetic roughening of the Fe surface at growth temperatures of 100-200° C due to the presence of step-edge barriers.
我们研究了通过分子束外延在室温至250°C的生长温度下沉积在富砷GaAs(0 0 1)-c(4×4)表面上的Fe(0 0 1)薄膜的外延、生长、结构和形貌。电子和X射线衍射(XRD)技术证明了Fe(0 0 1)[1 0 0]∥GaAs(0 0 1)[1 0 0]的外延生长。由XRD结果得出的残余应变与最近的应力测量结果一致。横截面透射电子显微镜显示室温薄膜的界面陡峭，并且在250°C时形成了约10nm厚的结晶Fe-Ga-As中间层。表面形貌对生长温度和退火的依赖性证明，由于存在台阶边缘势垒，在100-200°C的生长温度下Fe表面会发生动力学粗糙化。
