Creation of silicon vacancy in silicon carbide by proton beam writing toward quantum sensing applications

Single photon source (SPS) is a key element for quantum spintronics and quantum photonics. It is known that several color centers such as silicon vacancy (V-Si), divacancy (VSiVC), carbon antisite carbon vacancy pair (CSiVC), in silicon carbide (SiC) act as SPSs. Spin (S = 3/2) in VSi in SiC can be manipulated even at room temperature and the intensity of its photoluminescence (PL) changes depending on the spin states (m(S) = +/- 3/2 or m(S) = +/- 1/2). Since PL from VSi is in the near infrared region (around 900 nm), it is expected that VSi is applied to quantum sensor especially for biological or medical applications. In this review, we discuss quantum sensing based on V-Si in SiC. Also, we discuss energetic particle irradiation, especially proton beam writing (PBW), in which proton microbeams with MeV range are used, as a method to create V-Si in SiC since PBW can create V-Si in certain locations with micrometer accuracy and this is very useful to introduce V-Si in electronic devices without the degradation of their electrical characteristics.