Influences of hydrogen ion irradiation on NcVsi− formation in 4H-silicon carbide

Nitrogen-vacancy (NCVSi−) center in 4H-SiC is spin defect with near-infrared luminescence at room temperature and a promising candidate for quantum technologies. This paper reports on NCVSi− center formation in N-doped 4H-SiCs by hydrogen ion irradiation and subsequent thermal annealing. It is revealed photoluminescence for NCVSi− centers suddenly appears above the fluence of 5.0 × 1015 cm−2 when annealed at 1000 °C. Appearance of a threshold fluence for their formation and/or activation has not been observed for other energetic particle irradiations. The possible mechanism is discussed based on the kinetics of hydrogen-related complexes and the majority carrier depletion caused by irradiation induced damage

Formation of nitrogen-vacancy centers in 4H-SiC and their near infrared photoluminescence properties

NCVSi− centers in SiC [nitrogen-vacancy (NV) centers], which produce near-infrared (NIR) photoluminescence (PL) at room temperature, is expected to have applications as quantum sensors for in vivo imaging and sensing. To realize quantum sensing using NV centers, clarification of the formation mechanism as well as control of the high-density formation is necessary. This paper reports a comprehensive investigation on the NIR-PL properties originating from NV centers in high purity semi-insulating and nitrogen (N) contained 4H-SiC substrates formed by ion beam irradiation and subsequent thermal annealing. It is shown that NV centers are exclusively formed by the contained N as impurities rather than the implanted N, and also the heavier ion irradiations induce the NV center formation effectively than the lighter ion irradiations. The study on thermal annealing at different temperatures reveals that the optimal temperature is 1000 °C. From the results of temperature dependence on the PL intensity, it is shown that little thermal quenching of the PL intensity appears at room temperature and the PL signal is collected even at 783 K. The formation mechanism of NV centers is also discussed based on the obtained results

Effects of Nitrogen Impurity Concentration on Nitrogen-Vacancy Center Formation in 4H-SiC

We investigated the effect of nitrogen concentration of 4H-SiC epilayer on the near-infrared (NIR) photoluminescence (PL) intensities from nitrogen-vacancy (NV) centers and found that the NIR-PL emission increased with increasing N concentration. It can be concluded that the effects of irradiation fluence on PL intensity of NV centres in SiC strongly depends on the primary N concentration.International Conference on Silicon Carbide and Related Materials 201

Effects of Nitrogen Impurity Concentration on Nitrogen-Vacancy Center Formation in 4H-SiC

Spin defects of which states can be manipulated in Silicon Carbide (SiC) have drawn considerable attention because of their applications to quantum technologies. The single negatively-charged pairs of VSi and nitrogen atom (N) on an adjacent C site (NcVsi- center) in SiC is suitable for them. This paper reports the formation of NcVsi- centers on 4H-SiC epilayers with different nitrogen concentrations using light/heavy ion irradiation and subsequent thermal annealing. The formation of NcVsi- centers is characterized by the near infrared photoluminescence (PL) spectroscopy. It is shown that the PL intensity from NcVsi- centers depends on the N concentration and the ion irradiation conditions. The PL intensity increases monotonically with increasing the Nconcentration when the N concentration is above 2.6×10^16 cm^-3 , whereas no linear correlation between them does not appear below that N concentration. Although the PL intensity increases with increasing defects induced by ion irradiation, the PL quenching due to neighboring residual defects appear at above the areal vacancy concentration of 10^17 vac/cm^2 and the broad Raman scattering spectra originated from vibration modes of amorphized regions hinder the PL from NcVsi- centers at above 10^18 vac/cm^2. The formation mechanism and the charge state stability of NcVsi- centers are discussed based on the obtained results

Creation of nitrogen-vacancy centers in SiC by ion irradiation

Color centers which act as stable single photon emitters (SPEs) in wide bandgap semiconductors are key elements for quantum technologies. Silicon carbide (SiC) is regarded as a promising host material for qubit/quantum sensor. It was reported that negatively charged nitrogen-vacancy (NcVsi-) center in SiC (S=1) act as SPS with its zero phonon line (ZPL) around 1170 ~1250 nm. However, detailed characteristics of NcVsi- center in SiC have not yet been clarified since the creation methods for NcVsi- have not yet been established.In this study, various energetic charged particles such as protons, nitrogen (N), silicon (Si) and iodine (I) ions were irradiated into n-type and high purity semi-insulation (HPSI) hexagonal (4H) SiC and subsequently annealed up to 1100C. The creation of NcVsi in SiC are evaluated on the basis of photoluminescence (PL) characteristics.30th International Conference on Defects in Smiconductors (ICDS-30

Near Infrared Photoluminescence of NCVSi- Centers in High-Purity Semi-Insulating 4H-SiC Irradiated with Energetic Charged Particles

This paper reports optical properties of negatively charged NcVsi- centers in silicon carbide (a nitrogen substituting for a carbon atom adjacent to a silicon vacancy) whose emission wavelength is 1100-1500 nm at room temperature. High-purity semi-insulating (HPSI) 4H-SiCs are implanted with high energy N ion beams and subsequently thermally annealed to form NcVsi- centers. We investigated a wide range of N ion implantation dose using a micro ion beam implantation technique and observed the photoluminescence intensity from the SiC-NV centers. We show that under conditions of heavy implantation, the excitation laser power excites residual defects and their fluorescences interferes with the emission from the NcVsi- centers. These results allow us to clarifythe requirements to optically detect isolated single NcVsi- centers at lightly implanted conditions