| In situ transmission Fourier transform infrared (FTIR) spectroscopy was used to study atomic layer deposition on particles. The use of particles as substrates was necessary to achieve the high surface area required for transmission FTIR studies. Pressing the powders into grids gave surface enhancements as high as 15,000 times when compared to a flat substrate. In addition, coating particles with ultrathin and conformal films is of technological importance for numerous applications. Atomic layer deposition is an ideal technique to apply thin conformal coatings with monolayer resolution on particles. This allows for the modification of a particle's surface while only minimally affecting the overall properties of the particle.;In this thesis, atomic layer deposition (ALD) was demonstrated as a technique for coating particles. The demonstrations in this thesis include coating BN particles with Al2O3 and SiO2 films and coating ZrO2 particles with BN and TiO2 films. Transmission FTIR spectroscopy was used to monitor the surface chemistry during nucleation and growth of the thin films during ALD. Additionally, transmission FTIR spectroscopy was used to monitor the growth of bulk vibrational modes corresponding to the deposition of material on the particles. Ex situ analysis included X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). XPS and TEM provided information on the conformality and thickness of the deposited films on the particles. In contrast to Al2O3, SiO2 and TiO2 ALD, BN ALD had not been previously demonstrated. Transmission FTIR spectroscopy was used to study the alternating reactions of BCl3 and NH3 to deposit BN and the progressive growth of bulk BN modes. |
