Abstract
The second quantum revolution, which began in the 1980s, aims to exploit the properties of quantum mechanics to design and build innovative devices.Optically active point defects in semiconductors are one of the studied quantum systems and have the particular feature of behaving like artificial atoms in the solid state.This implies that, isolated on an individual scale, they exhibit single photon emission that can be used for quantum communications.In addition, some defects have a detectable and controllable electronic or nuclear spin state that can be used as a quantum memory or sensor.Silicon is the main semiconductor of the electronics industry and the ideal platform for large scale nanofabrication of quantum circuits.However, fluorescent defects in this low-bandgap semiconductor have been little studied for quantum applications, with the first isolation of an optically active defect only recently reported.The study of these defects initially focused on the G centre, a carbon-based defect, which exhibits photoluminescence emission in the wavelengths used in optical fibre telecommunications, and has a non-zero spin state that can be exploited for quantum technologies.In this context, carbon-implanted silicon samples were explored, not only ensuring the creation and detection of single G centres, but also revealing multiple unidentified individual fluorescent defects emitting in the near infrared.Alongside this exploration, silicon-implanted samples were analysed, allowing the first isolation of the W centre, an intrinsic defect in silicon.On these different emitters, optical spectroscopy studies coupled with single photon emission analysis have revealed properties not accessible by ensemble measurements.The observation of individual defects embedded within silicon on insulator wafers opens the possibility of exploring defect-based quantum technologies in silicon, such as integrated quantum photonics and quantum communications.The next step would be to demonstrate control of the spin states, which could lead to the development of an efficient spin-photon interface operating at the telecommunications wavelength.