Luminescence of InAs and AlInAs Single Quantum Dots
A system of quantum dots on the basis of Al<sub>x</sub>In<sub>1-x</sub>As / Al<sub>y</sub>Ga<sub>1-y</sub>As solid solutions has been studied. The usage of broadband Al<sub>x</sub>In<sub>1-x</sub>As solid solutions as the basis of quantum dots makes it possible to expand considerably the spectral emission range into the short-wave region, including the wavelength region near 770 nm being of interest for the design of aerospace systems of quantum cryptography. The optical characteristics of single Al<sub>x</sub>In<sub>1-x</sub>As quantum dots grown according to the Stranski-Krastanov mechanism are studied by the cryogenic microphotoluminescence method. Hanbury Brown and Twiss experiment has been carried out to measure the photon statistics. Photon correlation function demonstrates a clear photon antibunching effect, what is a direct evidence of single photon emission by Al<sub>x</sub>In<sub>1-x</sub>As single quantum dots. The fine structure of exciton states of quantum dots is studied in the wavelength region near 770 nm. It is shown that the splitting of exciton states is comparable with the natural width of exciton lines, which is of great interest for the design of emitters of pairs of entangled photons on the basis of Al<sub>x</sub>In<sub>1-x</sub>As quantum dots.