Single InAs1−xPx/InP quantum dots as telecommunications-band photon sources

The optical properties of single InAs${}_{1\ensuremath{-}x}$P${}_{x}/$InP quantum dots are investigated by spectrally resolved and time-resolved photoluminescence measurements as a function of excitation power. In the short-wavelength region (below 1.45 $\ensuremath{\mu}$m), the spectra display sharp distinct peaks resulting from the discrete electron-hole states in the dots, while in the long-wavelength range (above 1.45 $\ensuremath{\mu}$m), these sharp peaks lie on a broad spectral background. In both regions, cascade emission observed by time-resolved photoluminescence confirms that the quantum dots possess discrete exciton and multiexciton states. Single photon emission is reported for the dots emitting at 1.3 $\ensuremath{\mu}$m through antibunching measurements.