Optical and structural study for DLC thin films prepared by plasma jet

الملخص EN

Diamond-like carbon (DLC) homogeneous thin films were deposited from cyclohexane (C 6 H 12 ) liquid by using a plasma jet system which operates with alternating high voltage 7.5 kv and frequency 28 kHz.

The optical and structural properties and chemical bonding of these films were investigated.

In this work, the effect of changing the distance between the substrate and the plasma torch (2, 2.5 and 3 cm) was studied.

The flow rate of argon gas which used to generate the plasma was fixed (0.5 L/min).

These films were characterized by UV–Visible spectrophotometer, X-ray diffractometer (XRD) and scanning electron microscopy (SEM) and Fourier transformation infrared spectroscopy (FTIR).

The maximum absorption (λmax) appears around 312, 298.3 and 293.2 nm at the three distance between plasma torch and the substrate 2.5, 2 and 3 cm, respectively.

The values of the optical energy gap are 3.47, 3.65 and 3.76 eV at a different distance (2, 2.5 and 3cm), respectively.

In XRD diffraction pattern, The occurrence of diamond peaks and graphite peaks in the x-ray spectrum for these films Indicates that there is an occurrence of local ordered sp3 and sp2 for carbon domains and graphite respectively.