Abstract
M. Ing. (Electronic and Electrical)
Porous silicon has been obtained by anodizing monocrystalline silicon in hydrofluoric
acid solutions. The experimental conditions needed to obtain this material are
described. A scanning electron microscopy study revealed the morphology of the
pores. The diffusion-limited model is the current accepted model explaining the
formation of porous silicon. The structure of porous silicon formed on lightly doped
n-type silicon does, however, not agree with the morphologies predicted by the basic
model. The model was·therefore extended to include the n-type observations. The
observed straight pores, the fluctuation of pore length and the double layered
structure were succesfully simulated. Visible photoluminescence were obtained from
p-type porous silicon. The properties of the emitted light were investigated together
with the quantum confinement and siloxene models describing this behaviour of
porous silicon. The effect of the anodizing parameters on the electroluminescence
visible during the anodic oxidation of porous silicon were investigated leading to
additional proof of the quantum confinement model. A model describing the band
structure of the silicon-electrolyte system during electroluminescence is proposed.