Stable photoluminescence and electroluminescence from porous silicon

By carefully controling the nanocrystallite surface passivation, it is possible to make light-emitting porous silicon essentially inert and to stabilize its photoluminescence. Using this material, which we call silicon-rich silicon oxide (SRSO), stable and efficient porous silicon light-emitting devices (LEDs) emitting in the visible have been manufactured. The material's optimization, device design, and device fabrication that have allowed us to achieve these goals are discussed. The electrical and optical properties of the LEDs are described and explained by a model for carrier transport and recombination. By changing the preparation and processing conditions and by doping the SRSO layer with impurities such as erbium, photoluminescence and electroluminescence at longer wavelengths have been demonstrated. (C) 1997 Elsevier Science S.A.