View of hBN sample after laser irradiation with pulse duration of 150 ps (a) 5 ps (b), and 0.45 ps (c). Ambient gas is at with traces of . , , (a) and 248 nm [(b)–(c)].
Raman spectra (488 nm, 40 mW) of the laser-irradiated hBN samples. The irradiation conditions are 150 ps/266 nm, (a) and 0.45 ps/248 nm [(b)–(d)]; the laser fluence is above [(a) and (c)–(d)] and below (b) the ablation threshold. The ambient gas is at 500 bar [(a)–(c)] with oxygen content of 20 mbar (a) and [(b)–(c)]. Ne gas at 500 bar pressure is used instead of in (d).
Raman spectra (488 nm) of the irradiated hBN samples (0.45 ps, 248 nm, , ambient gas at 500 bar, and oxygen pressure ), taken at laser power varied from 4 to 40 mW. Four reference spectra of bulk hBN, irradiated pyrolytic BN, multiwall BN nanotubes, and graphite (c) taken at 40 mW cw-laser power are presented in the upper part of the figure.
TEM images [(a), (c), and (e)–(f)] and electron diffraction patterns [(b and (d)] of fresh [(a) and (b)] and irradiated [(c)–(f)] hBN samples. The irradiation condition are 5 ps/248 nm, , ; ambient gas is at with traces of .
TEM image (a) and electron diffraction pattern (b) of the hBN nanorod appeared in the irradiated area (irradiation condition as presented in Fig. 4).
EELS analysis of hBN nanorod: (irradiation condition as presented in Fig. 4).
Fluorescence excitation spectra (, not corrected for the primary monochromator efficiency) and fluorescence spectra of the original (a) and transformed (b) hBN samples .
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