  We created 4 p-Si models and 4 p-Si:H models all with 50% porosity. The
models contain 32, 108, 256 and 500 silicon atoms with a pore parallel to one
of the simulational cell axes and a regular cross-section. We obtained the
densities of states of our models by means of ab initio computational methods.
We wrote a code to simulate the emission spectra of our structures considering
particular excitations an decay conditions. After comparing the simulated
spectra with the experimental results, we observe that the position of the
maximum of the emission spectra might be related with the size of the silicon
backbone for the p-Si models as the quantum confinement models say and with the
hydrogen concentration for the p-Si:H structures. We conclude that the quantum
confinement model can be used to explain the emission of the p-Si structures
but, in the case of the p-Si:H models it is necessary to consider others
theories.
