[19a-B3-1~9] 6.2 Carbon-based thin films

9:00 AM - 9:15 AM JST(12:00 AM - 12:15 AM UTC)

[19a-B3-1] Photochemical Transparency of Amorphous Carbon Thin Films by F₂ Laser

〇Masayuki Okoshi¹, Satoshi Okuzono¹ (1.NDA)

Keywords:

amorphous carbon,transparency,F2 laser

In this paper, we used an F₂ laser with a wavelength of 157 nm to photoexcite the surface of an a-C thin film, and simultaneously photodecompose atmospheric oxygen molecules O₂ into excited singlet oxygen atoms O(¹D). The results showed that O(¹D) atoms can photochemically etch sp² carbon in thin films significantly better than triplet oxygen atoms O(³P). Thus, we found that the surface layer of the a-C thin film was photochemically modified to be transparent. In X-ray photoelectron spectroscopy, the intensity of the C 1s peak originated to sp² carbon decreased. The refractive index was also slightly lowered, probably due to lowering film density. The electrical resistivity slightly decreased upon F₂ laser irradiation and remarkably decreased as the substrate was heated, exhibiting low bandgap properties.