Spectroscopic depth profiling

The film thickness and retractive index were calculated using spectroscopic ellipsometry. X-ray photoelectron spectroscopy (XPS) was used for composition analysis. Auger electron spectroscopy (AES) and secondary ion mass spectroscopy (SIMS) was used to investigate the depth profiles of the film. 

Because electron-spectroscopic and ion-scattering methods yield information about the first seven atom layers, applying these techniques to metal-hydrogen kinetic problems requires incorporating depth-profiling capability. That is, an argon-sputtering gun must be incorporated into the analysis system to remove undesired surface material up to several nanometers deep. 

Surface chemical changes created by these surface chemical reactions will be monitored by Electron Spectroscopy for Chemical Analysis (ESCA)(2), a very powerful spectroscopic technique for investigating surface compositions extending from 1-20 monolayers in depth from the surface. When the spectrometer is equipped with angle resolution capability, it also offers a means of non-destructive depth profiling of the upper 50A of substrate layers. 

Victorian brown coal occurs in five major lithotypes distinguishable by color index and petrography. Advantage has been taken of a rare 100 m continuous core to compare and contrast chemical variations occurring as a function of lithotype classification. For many parameters there is a much greater contrast between the different lithotypes than there is across the depth profile of (nearly) identical lithotypes. Molecular parameters, such as the distributions of hydrocarbons, fatty acids, triterpenoids and pertrifluoroacetic acid oxidation products, together with gross structural parameters derived from IR and C-NMR spectroscopic data, Rock-Eval and elemental analyses and the yields of specific extractable fractions are compared. 

X-ray photoelectron spectroscopic(XPS) analysis with argon-etching gives surface and depth profile of catalyst composition[20]. Figure 2 shows enriched Te-content at surface of Te/Mo=... 

Some new developments of two-dimensional spectroscopy are discussed. As a specific example, two-dimensional correlation analysis of a polymer laminate film using several different spectroscopic techniques is presented. The versatility of this technique was developed using depth-profiling photoacoustic spectroscopy, mid-and near-IR dynamic rheooptical developments, and spectroscopic imaging microscopy. Spatial and temporal variations of near-IR spectra are effectively analysed by the two-dimensional correlation technique. Step-scanning FTIR spectrometers provide an opportunity to obtain desired spectral information often difficult to obtain by the conventional rapid-scanning technique. 12 refs. 

Photothermal methods may be used for depth profiling spectroscopic and/or thermal properties of condensed-phase samples because the sampling distance of the thermal waves may be controlled by varying the modulation frequency (as in eqn [1]) or the observation time (as in eqn [2]). 

Photothermal spectroscopy may be used to measure physical and chemical properties of sample as a function of depth. This depth profiling may be thermal, spectroscopic, or a composite of the two. Thermal depth profiling is achieved by irradiating the sample at opaque wavelengths. The magnitude and phase of the surface temperature is measured at several modulation frequencies and subsurface properties are deduced by subsequent data analysis. 

Muller F, Bimer A, Gosele U, Lehmann V, Ottow S, Foil H (2000) Structuring of macroporous silicon for applications as photonic crystals. J Porous Mater 7 201-204 Nassiopoulu AG, Kaltsas G (2000) Porous silicon as an effective material for thermal isolation on bulk crystalline silicon. Phys Stat Solidi (a) 182 307 Nava R, de la More MB, Taguena-Martinez J, del Rio JA (2009) Refractive index contrast in porous silicon multilayers. Phys Stat Solidi C6 1721-1724 Pettersson L, Hultman L, Arwin H (1998) Porosity depth profiling of thin porous silicon layers by variable angle spectroscopic ellipsometry a porosity graded layer model. Appl Optics 37(19) 4130 136... 

Parratt LG (1954) Surface studies of solids by total reflection of X-rays. Phys Rev 95 359 Pettersen LA, Hultman L, Arwin H (1998) Porosity depth profiling of thin porous silicon layers by use of variable angle spectroscopic ellipsometry a porosity graded-layer model. Appl Opt 37 4130... 

I. Noda, G. M. Story, A. E. Dowrey, R. C. Reeder, C. Marcott. Applications of two-dimensional correlation spectroscopy in depth profiling photoacoustic spectroscopy, near-infrared dynamic rheooptics, and spectroscopic imaging microscopy. Makwmol Chem Macromol Symp 119 1,1997. 

Photoacoustic spectroscopy and related photothermal products [7] are well-established spectroscopic techniques. The photoacoustic technique, apart from providing direct optical absorption spectra, can also be used to perform depth profile analysis, and characterisation of thermal properties. In addition, there has been a substantial development of new versatile and competitive instrumentation and experimental methodologies suitable for use in daily practice [6,7]. Further details on the photothermal wave phenomenon and its applications can be found in the books by Rosencwaig [6] and Almond [7] and in some of many published reviews on the subject [8-10]. 

Other methods, such as variable-angle spectroscopic ellipsometry (VASE), can be used to obtain a depth profile of the BHJ active layers in thin-films. However, the proper modeling of the refractive indices of BHJ components and fitting is challenging, and one must contend with the fact that most polymers are highly absorbing for wavelengths in the visible spectrum." ... 

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