Structural Analysis and Electrical Properties of Amorphous Carbon Thin Films

Abstract

The amorphous carbon (a-C) thin films have been developed by many researchers due to many superior properties. The aim of this research to study the structure of amorphous carbon thin film. Amorphous carbon was successfully prepared by carbonization of up to 200°C. Organic compounds that used in this research were coconut sap and its derivatives. The variation used in this research was a calcinating temperature ranging from 250°C, 400°C, and 600°C. Amorphous carbon powder was then mixed with aquades. Exfoliation process has been applied using an ultrasonic cleaner for 2 hours and then centrifuged at 4000 rpm for 30 minutes. Deposition technique used in this research was spin - coating. The X-ray diffraction pattern shows that the carbonization process produces amorphous carbon phase at diffraction angle of 2θ =15-30°. The infrared absorbtion in the region 500 to 4000 cm-1 was resolved into several peaks, which were assigned to C ̶ H, C ̶ O, C ̶ C, C=C and O ̶ H bonding. Photo Emission Spectroscopy (PES) was used to measure the percentage of sp2 and sp3 configuration in the sample. From the PES data, the percentage of sp2 configuration of coconut sap heated at 400°C is 55.32%. Four-point probe method was also used to measure the conductivity and band gap of each material, resulting in 2.67 – 8.33 S/m and 0.15 – 0.49 eV respectively.