Effect of precursor gas inlet position relative to hot wire cells in HWC-IP-PECVD systems for low-temperature graphene growth

Abstract

ABSTRACT Graphene growth at low temperatures was investigated by integrating a hot wire cell made from coil-shaped tungsten into a plasma-enhanced chemical vapour deposition (PECVD) system. It was found that the suitable position of the hot wire was such that the precursor gas comes out of the end of the gas pipeline and directly flows into the hot wire along its axis. This position puts the gas pipeline outside of plasma area, yielding uninterrupted plasma. The obtained films, which were grown at a low temperature between 290 °C to 300 °C, showed the presence of sharp G band in Raman spectra, indicating the presence of graphitic carbon structure and was confirmed by X-Ray Diffraction data. Also, sharp D band was detected in Raman spectra, which indicated that the film contains many defects. In addition to the nature of ion bombardment in the PECVD process, the defects were due to the addition of O-H functional groups and the formation of sp3 C-H in the samples, as shown in the FTIR spectra. Due to these defects, the Raman spectra obtained of the films showed very weak 2D bands, suggesting that our samples were in the form of graphene oxide.