A theory for semiconductor nanostructure reactivity to gas environment

A theoretical model has been developed to link the nanostructure geometry of porous silicon to its optical properties. Light emission and absorption energies have been calculated within a variational scheme, which includes a position-dependent boundary condition that reflects the surface chemistry. We show that the results of our measurements of both the photoluminescence (PL) quenching and peak position shift in the presence of oxygen can be accounted for by the theory. The model can be considered as a first building block of a general theory governing the functioning of semiconductor nanostructure-based gas sensors.