A mechanism of electroluminescence in silicon diodes with a high dislocation density

A new concept is suggested to explain the effect of dislocations on electroluminescence in silicon diodes. This concept is based on consideration of the spatial correlation between injected electrons and holes that recombine inside a dislocation core. This correlation leads to an increase in the probability of radiative recombination for electron-hole pairs. Two cases are analyzed. In the first case, the resulting current is controlled mainly by tunneling of electrons and holes along dislocations, which is followed by electron-hole recombination under the conditions of barrier lowering. In this situation, electroluminescence is not related to the fundamental absorption edge and the energy position of the electroluminescence band shifts to shorter wavelengths as either the temperature decreases or the applied voltage increases. In the second case, the diffusion-related component is prevalent in the total current. The radiative recombination of electron-hole pairs occurs in quasi-neutral regions and the electroluminescence exhibits an edge-related character. It is shown that the suggested mechanism may be responsible for a substantial enhancement of both the electroluminescence intensity and the quantum efficiency in silicon diodes with dislocations if the Shockley-Read-Hall lifetime is shorter than 10^?3 s.