A Gravimetric Technique to Determine the Crystallite Size Distribution in High Porosity Nanoporous Silicon

Abstract

Nanoporous silicon structures were investigated for application in nano-explosive devices, where the porous structure is impregnated by an explosive oxidant. A large specific surface area is required for the nano-explosive surface reaction, which is normally only achieved with small pore diameters. A small pore diameter will reduce the impregnation efficiency of the oxidant within the nanoporous layer. To optimize the nano-explosive performance, it was necessary to determine the relationship between specific surface area and pore dimension. A gravimetric technique is described whereby the specific surface area can be determined, as well as the statistical distribution of crystallite diameters in the nanoporous structure. It is shown that the high porosity nanoporous silicon is best modeled as an array of cylindrical crystallites, rather than an array of pores. It is also demonstrated that the statistical distribution of the crystallite diameters can best be described by a log-normal distribution.