và hình dạng đường Lorentz) vấn đề thực tế "là giải pháp kém này là không đủ để giải quyết sát với tần số rung động. thiết bị đo đạcTrong HREELS, một chùm electron năng lượng thấp monoenergetic tập trung trên bề mặt mẫu và các điện tử nằm rải rác được phân tích | 8 E Folkmann. In Ion Beam Surface Layer Analysis. O. Meyer G. Linker and o. Keppeler eds. Plenum New York 1976 pgs. 695 and 747. Early experimental evaluation of X-ray background in PIXE. 9 R. G. Musket-In Advances in X-Ray Analysis. GJ. McCarthy et al. eds. Plenum Publishing 1979 volume 22 . PIXE of c on and in Fe. 10 R. G. Musket. NucL . Phys. Res. B24 25 698 1987. PIXE of o on and in Be. 11 J. L. Campbell and J. A. Cookson. NucL Instr. Meth. Phys. Res. B3 185 1984. A review of thick-target PIXE. 12 R. G. Musket. Nucl. Instr. Meth. Phys. Res. 218 420 1983. Examples of simultaneous PIXE and RBS. 13 X. Zeng and X. Li. Nucl. Instr. Meth. Phys. Res. B22 99 1987. Details of fast transistorized on-demand beam for PIXE. 14 J. L. Campbell w. Maenhaut E. Bombelka E. Clayton K. Malmqvist J. A. Maxwell J. Pallon and J. Vandenhaute. Nucl. Instr. Meth. Phys. Res. B14 204 1986. Comparison of five PIXE spectral processing techniques. 15 J. A. Cookson and J. L. Campbell. NucL Instr. Meth. Phys. Res. 216 489 1983. Calculated effects of surface roughness on thick-target PIXE. PIXE 369 VISIBLE uv EMISSION REFLECTION AND ABSORPTION Photoluminescence PL 373 Modulation Spectroscopy 385 Variable Angle Spectroscopic Ellipsometry VASE 401 INTRODUCTION In this chapter three techniques using visible and UV light to probe the near surface regions of solids are described. In two of them Photoluminescence PL and Modulation Spectroscopy electronic transitions between valence and conduction bands excited by the incident light are used. Modulation Spectroscopy is simply a specialized way of recording the absorption spectrum as the wavelength of the incident light is scanned. The derivative spectrum is recorded by phase-sensitive detection as the temperature electric field or stress of the sample is modulated improving sensitivity to small spectral changes. PL on the other hand looks at the emission spectrum as the excited electronic states induced by the .
