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 (V _Si V _C), carbon antisite carbon vacancy pair (C_Si V _C), in silicon carbide (SiC) act as SPSs. Spin (S  =  3/2) in V _Si 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 V _Si is in the near infrared region (around 900 nm), it is expected that V _Si 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. (topical review)