ABSTRACT
The development of true single photon sources is of fundamental scientific and technological importance, but is particularly important for secure communication via quantum key distribution. Although modulated lasers have been used to successfully transmit quantum keys over relatively short distances, the use of modulated lasers, as opposed to true single photon sources, effectively reduces the bit rate of the system, and also renders the transmission insecure to certain types of eavesdropping attack. The electrically driven, surface acoustic wave (SAW) single photon source offers the prospect for relatively high frequency operation, and therefore high bit-rate. One of the key building blocks of this proposed device is a lateral, quantum well n-i-p junction, and we have previously developed a novel technique for the fabrication of such junctions. Using this technique we have fabricated lateral n-i-p junctions in InSb/lnAlSb quantum wells, and demonstrated acoustocharge transport between the n-type and p-type regions. Finally, we have also measured light emission from single InSb quantum wells. In this paper we describe the progress that these results represent towards the challenging goal of fabricating a mid-infrared single photon source.
