Crystalline Silicon (c-Si) is one of the most abundant and widely used semiconductors. Si is a semiconductor with indirect bandgap. The average reflectance of Si is about 30% in the visible range of wavelengths. Standard Si solar cells are not entirely useful in the infrared spectrum region. In order to make Si useful in a wide spectral range, the surface of Si is modified to reduce the reflectance of Si. The silicon thus modified is called Black Silicon (BSi).
This dissertation describes the model based on effective medium approximation to determine the effective optical constants, refractive index and extinction coefficient of BSi. The simulated optical properties of BSi are compared with the corresponding experimental values of BSi and c-Si. Application of Helmholtz’s law of optical reciprocity to the two-layer medium of BSi on crystalline silicon is examined. Influence of coatings and passivation on the optical properties of BSi is studied. The optical properties of passivation layers such as SiO2, Si3N4 and Al2O3, on BSi are investigated in the wavelength range of 0.4 to 2.4 μm. A novel approach of using BSi as absorbing material in uncooled microbolometers is studied. The performance parameters of BSi based microbolometer are evaluated
