High carrier injection for all-silicon laser

Presently, laser diodes are mainly used to convert electronic signals into optical signals in fast communication systems. They are manufactured with a wide variety of semiconductors different from silicon and the incorporation of these lasers in silicon layers leads to distortion of the signals, degradation of sensitivity, and limits the reliability. Silicon, with more than 95% of the international market share, dominates other semiconductors. A silicon laser source would provide the ideal improvement for future high-speed electronics. The structure of silicon limits its light-emitting efficiency and, despite the very fast development of silicon based electronics, optical applications of silicon devices have not been conducted thoroughly.

The question “which silicon device will be useful for transforming electronic signals into optical signals?” is still relevant today. This paper presents an advance in optoelectronic silicon devices since it introduces and formulates a process for the creation of an optical active layer inside silicon devices. A degradation of the structure is induced by hot carriers injection. The process has been controlled by the analysis of the junction characteristic. The authors suggest that the created defects disturb the lattice periodicity by creating energy states in the band gap of the silicon. The model is based on a population inversion associated with a defect layer for carrier confinement and an electrical stimulation of light is demonstrated. The emitted light is localized is an area close the emitter-base junction. The authors measure the amplification of emitted light, and they showed that defect layer appears as an optical cavity. This groundwork introduces practical ways for improving the optical properties of silicon devices for optoelectronic applications.