Low density 1.55 μm InAs/InGaAsP/InP (100) quantum dots enabled by an ultrathin GaAs interlayer

The authors report the formation of low density InAs/InGaAsP/InP (100) quantum dots (QDs) by metalorganic vapor phase epitaxy enabled by an ultrathin GaAs interlayer. For small InAs amount and low group-V flow rate, the QD density is reduced to below 10 QDs/µ m2. Increasing the group-V flow rate slightly increases the QD density and shifts the QD emission wavelength into the 1.55 µm telecommunication region. Without GaAs interlayer, the QD density is drastically increased. This is attributed to the suppression of As/P exchange during QD growth by the GaAs interlayer avoiding the formation of excess InAs

Electrical injection of a photonic crystal nanocavity

The possibility of electrical pumping of a single QD and the integration of such a device in an opto-electronic circuit would be a fundamental step towards achieving an on demand single photon source. In this paper we describe the fabrication process and preliminary results of a Light Emitting Diode (LED) integrated with a photonic crystal (PhC) nanocavity on a GaAs membrane. We demonstrate effective electric pumping of the QDs embedded into the membrane by contacting the doped layers (p and n) of the thin membrane, and the excitation of cavity modes of the PhC nanocavity fabricated on it at telecom wavelength

Lithographic and optical tuning of InGaAsP membrane photonic crystal nanocavities with embedded InAs quantum dots

Hexagonal symmetry InGaAsP membrane type cavities with embedded InAs quantum dots as active emitters were investigated by room temperature photoluminescence experiments at wavelengths near 1.50 µm. Cavities consisting of simple defects of just removing one or seven air holes were studied as well as modified cavities with additional holes decreased in size and shifted in position. The latter include the H0 cavity, in which only two adjacent holes were modified, but none removed. Low-Q cavity modes were observed after modification of the surrounding holes. The resonant frequencies were varied over a large range of lithographic parameters both by changing the lattice spacing or the size of the modified holes. More than 15 nm reversible dynamic optical tuning of the resonance modes was observed by changing the applied laser power up to 5 mW. For thermo-optic tuning, this corresponds to a heating of up to 200 °C