Silicon based IR light emitters

A new concept for Si-based light emitting diodes (LED) capable of emitting at 1.5 μm is proposed. It utilizes D-band radiation from dislocations in Si. Whether a dislocation network created in a reproducible manner by Si wafer direct bonding or dislocation loops produced by Si ion implantation are employed. It is also stated that dislocation loops do not lead to the strong band-to-band electroluminescence at 1.1 μm of p-n diodes, as it was predicted in the literature. A MOS-LED (Fig. A) and p-n LEDs emitting at 1.5 μm are demonstrated by the authors. The maximum efficiency that could be achieved at room temperature is close to 1%. Levels in the bandgap which are probably involved in the formation of the D1-line at 1.5 μm are revealed. Moreover, the observation of the Stark effect for the D1-line is reported. Namely, a red/blue-shift of peak position was observed in electro- and photo-luminescence when the electric field in the p-n LED was increased/lowered. This effect may allow realization of a novel Si-based light emitter with electric field modulated emission wavelength. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)