A bright future for silicon in quantum technologies

Abstract

Silicon is the most widely used material in microelectronic devices; integration of atomic impurities in silicon via doping during growth or ion implant is now widely used as it allows to form conventional transistors. Exploiting all the knowledge accumulated over the last 60 years in the context of the second quantum revolution that is now underway would help accelerate the commercialization of quantum technologies. Several works have already reported that silicon can be an optically active material with point-like defects emitting below the Si bandgap, both in ensemble emission and absorption in natural Si as well as in isotopically purified 28Si, even under electrical pumping. Very recently, the detection of individual impurities in silicon opened the door for further exploitation of this indirect bandgap material to applications in quantum technologies, including single photon emission at near-infrared frequency, matching the telecommunication band and optical detection of individual spins. Here, we describe the current state-of-the-art and discuss the forthcoming challenges and goals toward a reliable exploitation of these solid-state quantum-emitters in the context of quantum technologies. In particular, we examine opportunities, issues, and challenges in controlling defect formation and localization, extrinsic effects, and integration of optical devices.