Surface Analysisi under Air by UV Photoelectron Yield Spectroscopy

紫外光电子产率光谱（UPYS）是研究大气环境下固体样品表面性质的新工具。在本研究中，测量和分析了半导体和表面修饰金金属的UPY光谱，以阐明该技术作为空气中表面分析技术的能力。利用UPY光谱测定了不同类型硅片的光电子阈值能Et。Et和光电子产率Y反映了表面电子带结构的性质，并对杂质的类型和浓度敏感。利用eUPY光谱的导数可以很容易地区分硅片的（111）面和（100）面。通过对烷烃硫醇改性金金属的UPY光谱测定，确定了烃层中每个低能电子的逃逸深度约为11A。该值可与XPS测量的光电子值相当或小于该值，表明UPYS对样品表面非常敏感。功能修饰金的Et反映了表面官能团的偶极子振幅及其取向。

Ultraviolet photoelectron Yield spectroscopy (UPYS) is a new tool to investigate the surface property of the solid sampke under air atmosphere. In this study, the UPY spectra of semiconducters and surface modified gold metal were measured and andlyzed to elucidate the ability of this techniquw as surface analytical technique in air.The photoelectron threshold energy, Et of the various types of silicon wafers were determined form the UPY spectra. The Et and photoelectron Yield, Y reflect the nature of the surface electronic band structre and are sensitive to the type of the inpurity and its concentration. It is also indicated that the (111) and (100) faces of the silicon wafers can be easily distinguished by the use of derivative of th eUPY spectra.The escape depth of th every low energy electrons in hydrocarbon layr was determined to be about 11A by measuring the UPY spectra of alkane thiol modified gold metals. This value is vomparable or smaller than that for photoelectron neasured in XPS, indicating that the UPYS is very sensitive to the suface of the sample. The Et for the functinally modified gold metal reflects the dipole amplitude and its orientation of the surface functional group.