The Structural and Compositional Changes of Graphene Oxide Induced by Irradiation With 500 keV Helium and Gallium Ions

Abstract

Structural and compositional modification of 2D materials as graphene or graphene oxide (GO) are topical objects of nowadays due to their many technological applications. Ion irradiation of graphene based materials, as a method for improvement of their surface properties started recently. Ion mass, energy, and fluence are crucial for forming of GO electrical, optical, and mechanical properties. In this work, the GO films are irradiated with 500 keV He and Ga ions to different fluences. The ions with different masses and electronic/nuclear stopping power ratios, are chosen with the aim to examine mechanisms of radiation defect creation. The elemental composition of the GO is investigated using Rutherford back‐scattering (RBS) and elastic recoil detection analysis (ERDA) techniques. The structural and chemical changes are characterized by X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy and the electrical properties are determined by two‐point method. The RBS and ERDA analyses indicate deoxygenation and dehydrogenation of the irradiated GO surface. The thickness and the degree of O and H depletion depend on the ion mass. XPS and Raman spectroscopy show removal of oxygen functionalities and structural modifications leading to a decrease in the surface resistivity.

Comparison of GO and polymer microcapacitors prepared by ion beam writing

“…The increase in the C/O ratio indicates the graphene oxide reduction. 6,28 On the other side, the oxygen enrichment of irradiated PMMA relates to postimplantation oxygen diffusion via ion induced defects in the implanted layer. 34 The trend of the H/O ratio also disagrees in both materials; in GO, the H/O ratio…”

“…2 Graphene oxide (GO), the 2D carbon allotrope with high surface area, is a monoatomic lattice of carbon atoms decorated by epoxide, hydroxyl, carbonyl, and carboxyl groups, 4,5 which is an insulator in its pristine state due to a large portion of sp 3 hybridized carbons and can be converted to a semi-conductive or conductive state by a reduction that changes the sp 2 /sp 3 ratio. 6 The difference in conductivity of virgin GO and GO after reduction can be 10 orders of magnitude. 7,8 GO foils are attractive for microenergetic applications and especially for supercapacitor synthesis due to their high surface area and high dielectric constant, which vary in a wide range of values that are usually greater than 10 3 2,9 .…”

“…Graphene oxide (GO), the 2D carbon allotrope with high surface area, is a monoatomic lattice of carbon atoms decorated by epoxide, hydroxyl, carbonyl, and carboxyl groups, 4,5 which is an insulator in its pristine state due to a large portion of sp 3 hybridized carbons and can be converted to a semi‐conductive or conductive state by a reduction that changes the sp 2 /sp 3 ratio 6 . The difference in conductivity of virgin GO and GO after reduction can be 10 orders of magnitude 7,8 .…”

The effect of proton irradiation on the properties of a graphene oxide paper

“…Raman spectroscopy is used as a common tool for studying the structural composition of GOP, which is an invaluable method in graphene studies. 10,29,[31][32][33][34][35][36] It can be used to conrm the vibrational modes of surface functional groups and structural damage. Fig.…”

“…Combined with the above XRD and XPS analysis, the ndings indicate that although the amount of oxygen-containing functional groups is reduced compared to that in pristine GOP, many defects are retained aer the high uence irradiation process. 10,18,23,29,[32][33][34][35][36]41,43…”