Fig. 1. UV-Vis absorption spectra of CN-2 before and after HPHT-processing

Fig. 2. MIR absorption spectra of samples before (a) and after (b) HPHT-processing

Fig. 3. NIR absorption spectra of samples before (a) and after (b) HPHT-processing

Fig. 4. PL patterns of CN-2 before and after HPHT-processing
(a): 532 nm light excitation; (b): 633 nm light excitation

Fig. 5. Three-dimensional fluorescence spectra of CN-2 before and after HPHT-processing
Before heated: (a) Isometric three-dimensional projection; (b) Contour spectrum After heated: (c) Isometric three-dimensional projection; (d) Contour spectrum

Fig. 6. Raman spectra and XRD rocking curve of samples before and after HPHT-processing
Raman spectra (a): Before heated; (b): After heated XRD rocking curve (c): Before heated; (d): After heated

Fig. 7. Raman spectra and XRD rocking curve FWHM of samples before and after HPHT-processing
(a): Raman spectra FWHM of samples; (b): XRD rocking curve FWHM of samples