多价态金属氧化物混合相光学常数、相变规律和能带结构的光谱研究

Information on optical constants, composition, and thickness of multivalent uranium oxides is an important parameter for the utilization and evaluation of nuclear energy. In this proposal, multivalent vanadium oxide (V2O3, VO2, V2O5) and copper oxide (Cu2O, Cu4O3, CuO) and its mixed-phase and/or doped films will be selected as the research target. High-quality and large-area vanadium oxide and copper oxide and its doped films will be prepared, and their metal valence, composition, crystal quality and surface morphology will be analyzed. Using reflection/transmission, ellipsometric, and infrared spectroscopy, the effective optical constants and thicknesses of the vanadium oxide and copper oxide and its doped films in the deep ultraviolet to far-infrared spectral range will be obtained. The changes of optical properties of the vanadium oxide and copper oxide and its doped films, such as the electronic transition, band gap, absorption coefficient, and phonon mode, with the changes of the external field such as temperature will be revealed. The changes of the optical properties and band structures of the multivalent metal oxides near the phase transformation region will be systematically analyzed to clarify the intrinsic origin of the phase transformation characteristics. Based on the theoretical calculations and experimental data analysis, a new fitting model that can be used to analyze the optical constants and thicknesses of the mixed phases of multivalent oxides will be established. Our research results will provide a universal feasibility solution for the analysis of the thickness, composition and optical constants of uranium oxides and other multivalent mixed-phase oxides.

多价态氧化铀的光学常数、成分和厚度等信息是原子能利用与评价的一个重要的参数。本项目以多价态金属氧化钒和氧化铜混合相及其掺杂薄膜作为研究体系。制备出高质量大面积氧化钒和氧化铜及其掺杂薄膜，并对其金属价态、组分、结晶质量和表面形貌进行分析。采用反射/透射、椭圆偏振和红外光谱技术，获得氧化钒和氧化铜及其掺杂薄膜从深紫外到远红外光谱范围内的有效光学常数和厚度。揭示氧化钒和氧化铜及其掺杂薄膜光电跃迁、禁带宽度、吸收系数和声子模式等光学性质随温度等外场的变化规律。系统分析多价态金属氧化物在相变区附近光学性质和能带结构的变化，澄清其相变特性的本征来源。基于理论计算和实验数据分析，建立起可分析多价态氧化物混合相光学常数和厚度的光谱拟合模型。本项目的研究结果可为氧化铀等多价态混合相氧化物的厚度、组分和光学常数分析提供一种通用的可行性方案。

多价态氧化铀的光学常数、成分和厚度等信息是原子能利用与评价的一个重要的参数。本项目以多价态金属氧化铀、氧化铜和铜镓铬氧等氧化物薄膜作为研究体系。制备出高质量大面积氧化铀、氧化铜和铜镓铬氧薄膜，并对其金属价态、组分、结晶质量和表面形貌进行分析，提取了光学常数，进一步研究了能带结构和相变规律。取得的三个代表性研究成果包括：(1) 通过椭圆偏振光谱，测定了多价态金属氧化铀薄膜的光学常数、成分、能带结构和厚度, 获得了多价态氧化铀薄膜材料的光学常数，并测定U3O8和UO3的光学带隙分别为2.3 eV和1.0 eV，外延氧化铀薄膜中80%为U3O8, 20%为UO3。(2) 发现了镍掺杂浓度对氧化铜薄膜的光学常数、电子跃迁和光学带隙的作用规律；(3)发展了高质量氧化铜薄膜和铜镓铬氧薄膜制备工艺，系统研究了退火时间和温度场等对氧化物薄膜结晶质量、能带结构和声子模式的调控规律。本项目既研究了“金属氧化物制备和能带调控”等国际前沿科学问题，也为提取“氧化铀薄膜光学常数和成分”提供可行性方案，具有重要学术意义和应用价值，为我国在氧化铀的光学常数分析，进一步研究氧化铀表面的化学反应过程等国防军工领域的特色研究课题提供技术支撑。