Characterization and thermal stability of iodinated amorphous conducting carbon films

Abstract

In this work, we discuss the structural and transport properties of iodine intercalated amorphous conducting carbon (a-C: I) films prepared by vapor phase pyrolysis of maleic anhydride and iodine. X-ray photoelectron spectroscopy studies reveal the presence of iodine in the a-C: I samples. Microhardness measurements of the films show a decrease in the value of the hardness with an increase in iodine concentration. Iodine incorporation accounts for a change in electrical conductivity of the a-C samples. Magnetoresistance measurements performed on a-C: I samples show a decrease in the value of magnetoresistance. The thermal stability of a-C: I samples has been studied by thermogravimetric analysis, which is found to depend on the host structure and amount of intercalated iodine.

Semiconducting Properties of Nanostructured Amorphous Carbon Thin Films Incorporated with Iodine by Thermal Chemical Vapor Deposition

“…Therefore, it can be seen that the iodine doping has marked effects on the morphologies of the a-C samples as the a-C thin films incorporated with iodine showed more uniform and dense clustering of carbon atoms. This result is similar to that reported by Kumari et al 34) It should be pointed out that iodine doping has a considerable effect on the surface morphology of a-C thin films. 35) On the other hand, EDS was carried out to confirm the composition of the as-deposited a-C thin film and a-C:I thin film doped at 400 C. The results are shown in Fig.…”

“…Iodine incorporation into the a-C thin film accounts for the graphitization, resulting in the enhancement of the density of states, thereby increasing the conductivity of the a-C:I thin film. 34) From the plot, it is evident that iodine doping leads to the increase in electrical conductivity and showed that the iodine dopant could promote the neutralization of the dangling bonds in the a-C:I thin films. Therefore, this may be ascribed to the role of iodine atoms in assisting carbon atoms to form sp 2 bonds and become more graphitized, consequently decreasing the optical band gap in a-C thin films.…”

Light-Induced Organic Monolayer Modification of Iodinated Carbon Electrodes

“…It was observed that upon rinsing with ethanol, the peak at 618.1 eV diminished and is attributed to physisorbed iodine, suggesting the peak at 620.7 eV is attributed to iodine bound to carbon . Surfaces left under vacuum with iodine in the chamber, but without plasma formation, only presented iodine peaks at 618.1 eV, which also supports the hypothesis that the peak at 618.1 eV was due to physisorbed iodine while the 620.7 eV was attributed to iodine bound to carbon. , …”

“…53 Surfaces left under vacuum with iodine in the chamber, but without plasma formation, only presented iodine peaks at 618.1 eV, which also supports the hypothesis that the peak at 618.1 eV was due to physisorbed iodine while the 620.7 eV was attributed to iodine bound to carbon. 54,55 As the power of the plasma increased, it was observed that the amount of surface bound iodine increased relative to the intensity of the C 1s peak at 285 eV ( Figure S3). It was also noted that the longer the PPF was left in the plasma, the greater the amount of iodine chemically bound to the surface ( Figure S4).…”

Iodine Doping of Amorphous Carbon Thin Films Deposited by Thermal CVD

“…Due to the increasing of sp 2 content, the electrical conductivity of the films was improved and resistivity was decreased from 8.26×10 3 to 1.65×10 3 Ω.cm by iodine doping. The iodine incorporation in the a-C thin film plays a vital role in neutralization of the dangling bonds which changes the electronic properties of the film [12][13][14]. In order to decide the vibration mode between a-C thin film and iodine doped amorphous carbon thin film, the FTIR spectra were measured in the region from 2000 to 3000 cm -1 at room temperature.…”