Energetics with porous silicon

Abstract

The room-temperature energetic properties of porous silicon filled with an oxidant was accidentally discovered in 2002. Since then, this new branch of the porous silicon technology has made some progress, and several possible applications of this technology have been proposed. Of importance in the technology development are aspects like the type of oxidizer to be used, stabilization of the oxidizer in the pores, the effect of surface hydrogen on the long-term stability and energetic properties, the initiation of the reaction via electrical hot wires or laser illumination, the energy released from the reaction, as well as the reaction velocity. In this chapter, the above criteria are discussed, but emphasis is also placed on the porous silicon growth conditions, the effect of porous layer thickness, porosity, and the pore dimensions. The method to deposit the solid-state oxidizer in the pores via solvents is investigated, as well as the gas being generated during the energetic reaction. Some applications of this relatively new technology are proposed and discussed. As an interesting new development, the correlation between the nano-explosions of porous silicon and the appearance and development of the natural phenomenon of ball lightning, caused by small silicon particles covered with hydrogen atoms, is discussed.