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 10^21 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.