  A step-by-step evolution of an asymmetric Raman line-shape function from a
Lorentzian line-shape is presented here for low dimensional semiconductors. The
evolution reported here is based on the phonon confinement model which is
successfully used in literature to explain the asymmetric Raman line-shape from
semiconductor nano-structures. Physical significance of different terms in the
theoretical asymmetric Raman line-shape has been explained here. Better
understanding of theoretical reasoning behind each term allows one to use the
theoretical Raman line-shape without going into details of theory from first
principle. This will enable one to empirically derive a theoretical Raman
line-shape function for any material if information about its phonon
dispersion, size dependence etc is known.
