Universiti Teknologi Malaysia Institutional Repository

Structural and optical properties of diamond like carbon films using direct current plasma enhanced chemical vapor deposition

Ong, Wai Kit (2015) Structural and optical properties of diamond like carbon films using direct current plasma enhanced chemical vapor deposition. Masters thesis, Universiti Teknologi Malaysia.

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Abstract

The amorphous diamond like carbon (a - DLC) thin films were deposited in 3 hours on glass substrates at the vacuum pressure, 8.0 x 10-2 Torr ; deposition pressure, 4.0 x 10-1 Torr and deposition temperatures, 300 – 500 °C by using direct current plasma enhanced chemical vapour deposition (DC - PECVD) system with the precursor gas, 1 % of methane, 39 % of hydrogen and 60 % of argon. The (a - DLC) films which have completely been deposited were post annealed for 3 hours in the tube furnace at 500 – 700 °C with nitrogen ambient to obtain the nitrogen doped amorphous diamond like carbon (a:N - DLC) films. The characterizations were studied by using X-Ray Diffractometer, Energy and Dispersive Analysis of X-Ray, Fourier Transform Infrared Spectrometer, UV / VIS / NIR Spectrophotometer and Photoluminescence Spectrometer. The annealed films are verified as amorphous structure as discovered by X-Ray Diffractometer. It was revealed that carbon, nitrogen, oxygen and silicon are emitting the x-ray energy spectra at 0.28 keV, 0.39 keV, 0.5 keV and 1.74 keV, respectively. The infrared absorptions have shown at 880 cm-1 as C-H bending bonds, 1100 and 1220 cm-1 as C-N stretching bonds, 1300 cm-1 as C-C stretching bonds, 1600 cm-1 as C=N stretching bonds and 2200 cm-1 as C=N stretching bonds for the films annealed from 500 °C to 700 °C. Stretching bond has been observed when annealed at 500 °C and C=N stretching bond has formed when annealed at 700 °C. Moreover the transmittance of (a:N - DLC) films was increasing from 24.9 % to 70.7 % when annealing temperature increased from 500 °C to 700 °C; transition changed from allowed indirect transition, r = 2 to forbidden direct transition, r = 3/2; the optical band gap decreases from 1.60 - 0.85 eV at 500 - 650 °C, but increases to 1.62 eV at 700°C. With the fixed excitation wavelength at 245 nm within the measurement range of 200 – 800 nm, the emission wavelengths were obtained at 290 nm and 393 nm which correspond to n - n* transition and violet emission transition, 4P01/2 4P½, respectively.

Item Type:Thesis (Masters)
Uncontrolled Keywords:X-Ray Diffractometer, photoluminescence spectrometer
Subjects:Q Science > QC Physics
Divisions:Science
ID Code:81448
Deposited By: Narimah Nawil
Deposited On:23 Aug 2019 13:18
Last Modified:23 Aug 2019 13:18

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