The effect of dipole boron centers on the electroluminescence of nanoscale silicon p+−n junctions

Nanoscale silicon p+−;n junctions with very high concentration of boron, 5 1021 cm−3, are found to demonstrate interesting optical properties. Emission band dominated in near-infrared electroluminescence (EL) spectra possesses high degree of the linear polarization along preferred crystallographic axis which can be controlled by the lateral voltage applied in the plane of the p+−n junction. Such behavior together with the temperature dependence of the EL intensity is attributed to the presence of the self-compensating dipole boron centers, B+-B−, with negative correlation energy which are identified using the ESR technique in the nanoscale silicon p+−n junctions heavily doped with boron. The model of the recombination process though the negative-U dipole boron centers controlling the optical properties of the nanoscale silicon p+−n junctions is proposed.