Individual GaAs quantum emitters grown by droplet epitaxy on Si substrate

The integration of III-V nanostructures on silicon would open thè possibility to pursue integration between high performance quantum photonic devices and quantum informatimi technology devices based on CMOS circuitry on Si. In this work, we present thè growth and optical characterization of high quality GaAs quantum dots (as single photon emitters) grown by droplet epitaxy on Si substrates through thè deposition of a thin Gè layer. Droplet epitaxy [1] is intrinsically a lovv thermal budget growth, being performed at temperatures between 200 and 350 °C. This makes droplet epitaxy perfectly suited for thè realization of growth procedures compatible with back-end integration ofUI-V nanostructures on CMOS [2]. The contro! of thè growth kinetics allows thè fabrication of quantum dot samples with an arcai density down to few 10scm~~. Brighi and sharp emission lines are observed in a micro-photoluminescence experiment around 700 nm. with pure radiative excitonic lifetime and clear evidence of exciton-biexciton cascade. The achievement of quantum photon statistics is directly provedby antibunching in thè second order correlation function as measured with a Hanbury Brown and Twiss interferometer up to T=80 K, thus making thè single photon emitter working at liquid nitrogen temperature and compatible with present CMOS technology. Optical quality of thè GaAs quantum dots grown on Si substrate is almost comparable with quantum dots directly grown on GaAs substrates, clearly dernonstrating a new procedure for thè integration of high efficient light emitters, based on III-V semiconductors, directly on Si substrates, and opening thè route to wide applications to optoelectronics, photonics and quantum information technology. [1] N. Koguchi, S. Takahashi, T. Chikyow, J. Crystaì Growth 111 (1991) 688. [2] S. Bielli. C. Somaschini, S. Sanguinetti, N. Koguchi, G. Isella, and D. Chraslina, AppliedPhysics Lerters 95, 241102 (2009)