Modifications of WNxOy films by ion impact

Autor: Bun Tsuchiya, Masao Sataka, Noriaki Matsunami, Satoru Okayasu, T. Teramoto
Rok vydání: 2018
Předmět:
Zdroj: Surface and Coatings Technology. 355:84-89
ISSN: 0257-8972
Popis: We have investigated ion-impact-induced modifications of electronic- and crystalline-structures of WNxOy polycrystalline films on C-plane-cut-sapphire (C-Al2O3) substrate. Rutherford backscattering spectroscopy (RBS) of 1.8 MeV He+ ions leads to the composition, x = 1.1 ± 0.1 and y = 0.4 ± 0.2, respectively. X-ray diffraction (XRD) with Cu-Kα radiation shows a strong peak at the diffraction angle (2θ) ≈ 37° and a weak peak at ≈78°. These peaks are assigned as WN, referring to JCPDS data. No peaks were observed other than WN and C-Al2O3 (2θ = 41.7°). It appears that the electrical resistivity of unirradiated film (0.025 Ω cm) is reduced to 9 × 10−4 and 3 × 10−4 Ω cm by 100 keV Ne ions at 1.5 × 1017 cm−2 and 100 MeV Xe ions at 4 × 1014 cm−2, respectively, and that the XRD intensity decreases to ~1/240 and 1/170 by these ion impacts at 3 × 1015 cm−2 and 8 × 1012 cm−2, respectively. It also appears that the resistivity of unirradiated film increases with decreasing temperature from RT to 30 K like semiconductor and irradiated film shows very weak temperature dependence. Optical absorption monotonically decreases with increasing the wavelength from 200 to 2500 nm, indicating that the bandgap does not exist in the region of 0.5–6 eV and a small change was observed in the optical absorption by the ion impact.
Databáze: OpenAIRE
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