Browsing by Author "Aklog Abraham"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    Item
    Determination of Optical Constants of a thin Film Using Rotating Analyzer Ellipsometry of Multiple Angle of Incidence
    (Addis Ababa University, 2006-06) Aklog Abraham; Asfaw Araya (PhD)
    With multiple angle of incidence rotating analyzer ellipsometry, one can measure complex refractive index and the thickness of a very thin film simultaneously. This method is applied on conducting thin film polymer (MDMO-PPV/PCBM[1:1]) for five angles of incidence. In general, it is not possible to invert the Fresnel equations to obtain the complex index parameters, instead, the optical method has to be developed. In the model, the optical parameters are varied to minimize some chosen error function. And those parameters which give a minimum error function are taken to be the correct optical constants of the sample. Additional data are also gathered from absorption measurement, and the two independent measurements are compared. The complex refractive index and thickness of the sample for wavelengths 532 nm, 632.8 nm, 808 nm and 1064 nm are determined