Study of Dependence of Optical Parameters on the Size of Nanoporous Silicon Quantum Dot Through Energy Gap

Both nanocrystalline and nanoporous silicon show interesting optical properties. As the system size goes to nanoscale the optical band gap, radiative transitions, oscillator strength, absorption coefficient and dielectric function increase. The nanosilicon shows unusual optical properties which have tremendous importance for nanophotonics and optoelectronic applications. The purpose of this work is to study the optical behavior of nanoporous silicon cluster (quantum dot) with varying porosity and oxygen as well as hydrogen at the surface. In order to clarify the morphological effects such as surface passivation and porosity level of a nanoporous silicon on its optical properties, calculation of optical absorption coefficient, dielectric function and oscillator strength of porous silicon nanoclusters as a function of size (diameter) through energy gap have been discussed. The effects of nanoparticles size along with surface passivation and porosity level on optical band gap have also been investigated and compared with experiment. The porosity and surface effects are incorporated through some empirical parameters c and in our study. Keywords: Optical properties; quantum dot; porosity; optical band gap; surface effect