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Germanium is a promising material for electrically pumped light emitters integrated on silicon. In this work, we have investigated the room temperature electroluminescence of pure germanium diodes grown by metal organic chemical vapor deposition. The dependence of the optical response of the p-n diodes is studied as a function of the injected current. Both direct and indirect band gap recombinations are observed at room temperature around 1.6 and 1.8 m. The amplitude of the direct band gap recombination is equivalent to the one of the indirect band gap.

A strain Bir-Pikus Hamiltonian H st , based on a 20 band sps* k"p Hamiltonian H kp , is used to describe the valence band and the first two conduction bands over the entire Brillouin zone. This full-band k"p computation of the carrier dispersion relation is used to calculate electron and hole effective masses in strained silicon. Hole density of states masses are found to be very temperature dependent whereas electron effective masses can be considered temperature independent to first order.

We have fabricated light-emitting diodes on Si operating in the near-infrared. The active region of the p–i–n diodes consists of Ge/Si self-assembled quantum dots. The Ge islands were grown in an industrial 200 mm single-wafer chemical vapor deposition reactor. The photoluminescence and the electroluminescence of the islands are resonant in the spectral range around 1.4–1.5 μm wavelength. The electroluminescence is observed up to room temperature.