Measurement of Orientation in Organic Thin Films

As the potential for applications utilizing oriented thin films grows, so grows the need for accurate, reliable measurements of molecular orientation and surface coverage. Recent work in our laboratory has been directed toward this goal. In this paper the theoretical and experimental effects of surface roughness and the width of the molecular orientation distribution on spectroscopically measured orientation angles are reviewed, the combination of linear and nonlinear spectroscopic techniques for accurate determination of both the mean and width of an orientation distribution is described, and the theory and methodology necessary to obtain orientation-insensitive surface coverage measurements by second harmonic generation for adsorption isotherm and kinetics investigations are reviewed.