InAs quantum dots for quantum information processing

InAs quantum dots attract much interest because of their potential application in quantum information processing. In this paper, two wafers of self-organized InAs quantum dots incorporated in p-i-n junction structures are investigated with both photoluminescence and electroluminescence: one has a single layer of uniform quantum dots at low density; the other has vertically-stacked double layer quantum dots with graded densities across the wafer. For the single layer dot wafer, single-photon emission has been obtained successfully, by pumping optically and electrically at high repetition rates. The coupling between vertically stacked double dots has been observed from the abnormal Stark shifts and from anticrossings in photoluminescence and electroluminescence spectra.