Kuschel Olga, Dieck Florian, Wilkens Henrik, Gevers Sebastian, Rodewald Jari, Otte Christian, Zoellner Marvin Hartwig, Niu Gang, Schroeder Thomas, Wollschläger Joachim
Fachbereich Physik, Osnabrück University, Barbarastr. 7, Osnabrück D-49069, Germany.
Center of Physics and Chemistry of New Materials, Osnabrück University, Barbarastr. 7, Osnabrück D-49069, Germany.
Materials (Basel). 2015 Sep 18;8(9):6379-6390. doi: 10.3390/ma8095312.
Praseodymia films have been exposed to oxygen plasma at room temperature after deposition on Si(111) via molecular beam epitaxy. Different parameters as film thickness, exposure time and flux during plasma treatment have been varied to study their influence on the oxygen plasma oxidation process. The surface near regions have been investigated by means of X-ray photoelectron spectroscopy showing that the plasma treatment transforms the stoichiometry of the films from Pr2O3 to PrO2. Closer inspection of the bulk properties of the films by means of synchrotron radiation based X-ray reflectometry and diffraction confirms this transformation if the films are thicker than some critical thickness of 6 nm. The layer distance of these films is extremely small verifying the completeness of the plasma oxidation process. Thinner films, however, cannot be transformed completely. For all films, less oxidized very thin interlayers are detected by these experimental techniques.
通过分子束外延在Si(111)上沉积后，镨薄膜在室温下暴露于氧等离子体中。改变了诸如薄膜厚度、暴露时间和等离子体处理期间的通量等不同参数，以研究它们对氧等离子体氧化过程的影响。通过X射线光电子能谱对表面附近区域进行了研究，结果表明等离子体处理将薄膜的化学计量从Pr2O3转变为PrO2。如果薄膜厚度大于6nm的某个临界厚度，通过基于同步辐射的X射线反射率和衍射对薄膜的体相性质进行更仔细的检查证实了这种转变。这些薄膜的层间距极小，证实了等离子体氧化过程的完整性。然而，较薄的薄膜不能完全转变。对于所有薄膜，通过这些实验技术检测到氧化程度较低的非常薄的中间层。
