A series of experiments is presented in which a Bomem DA8 FT spectrometer is used as the main analytic instrument to clarify different effects in materials research. Our applications of the instrument range from absorbance measurements in semiconducting materials to reflectance measurements on superconducting thin films. Effects such as the change in optical absorbance for C60 films are observed and confirmed by transport measurements. The results of ion implantation processes on boron carbide (B4C) can be monitored by spectral measurements and indicate that the mechanical properties of the second hardest material, after diamond, can be adequately modified for easier machining.
A new rapid thermal diffusion (proximity RTD) method, utilizing spin-on dopant (SOD) layers, was reported recently. This technique is based on an evaporation-gas phase diffusion- adsorption-surface reaction-diffusion in Si scheme. In this paper we use FTIR spectroscopy to investigate a relationship between the SOD layer structure/composition and its doping efficiency, as determined by sheet resistance (RS) measurements, for a phosphorus diffusion case.
Some preliminary room-temperature measurements on thin-films superconductors using Dispersive Fourier Transform Spectroscopy (DFTS) in reflection are presented. Directly measured phase and amplitude reflectivity spectra in visible light are used to illustrate experimental difficulties when trying to determine optical properties of these materials. Some observations about the surface quality of the samples are discussed in connection with the obtained results.
We present a Fourier Transform spectrometer where as an interferogram, fringes of equal thickness (Fizeau fringes) are recorded instead of the usual fringes of equal inclination (Haidinger rings). An image of the Fizeau fringes being formed on the diode array of a CCD camera allows us to scan the interferogram without moving a mirror or any other element. As the entire interferogram is registered at the same time, AC and even pulsed light sources can be analyzed. The disadvantage is low spectral resolution because the maximum path difference is limited by the size of the diode array.
We present an UV-VIS Fourier Transform spectrometer with dynamic alignment and, in addition, automatic adjustment of the moving mirror before start and at each change of translation direction. In dynamic alignment the phase difference of laser interferograms from three points of the field of view is used to activate transducers holding the moving mirror. Whenever a run of the mirror is finished there is no interferogram for a few moments till the next run starts. The direction of translation is now opposite and due to the discontinuity of frictional forces in the drive there can be a misalignment of the moving mirror. If the misalignment leads to a phase difference greater than (pi) between the laser interferograms, correct alignment cannot be refound. To overcome this difficulty one can generate many laser interferograms instead of only three. Unless the interferograms from neighbor spots are out of phase by more than (pi) , the mirror can be realigned. Another solution of the problem which we present here is to modify the tilt of the moving mirror by means of piezo translators until the visibility of the interferogram of an expanded laser beam is at maximum.