Influence of substrate temperature on graphene oxide thin films synthesis by laser ablation technique

Abstract

In this paper, we studied the influence of the substrate temperature (Ts) on the deposition of carbon thin films by the pulsed laser deposition technique. Thin films were synthesized using a highly oriented pyrolytic graphite target, which was irradiated by the fundamental harmonic (1064 nm) of a Nd:YAG pulsed laser. In the experimental conditions, the Ts varied from room temperature to 500 °C, the gas pressure (oxygen, 50 mTorr) remained the same for all samples, and the ablation time was 5 min for each thin film. The samples were characterized by x-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy in conjunction with energy dispersive x-ray spectroscopy, atomic force microscopy, and contact angle measurement. The characterization results allowed us to determine that the thin films deposited on silicon substrates at 400 and 500 °C (samples S1 and S2) were multilayers graphene oxide. From XRD, Raman spectroscopy, and FTIR results, we concluded that the degree of oxidation and graphitization of the carbon thin films were influenced by the Ts. Additionally, the contact angle measurement showed that for samples S1 and S2, the contact angle was greater than 94°, and for samples S3 and S4 (amorphous carbon), it was less than 62°.