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Graphene oxidation

Graphene oxidation. Graphene oxidation is used to create a single layer graphene sheet. Graphene layers produced Oxidation experimental procedure. Sample oxidized at 450 o C for 10 min; Sample heated at 550 o C for 10 min; Sample heated at 550 o C for 20 min;

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Graphene oxidation

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  1. Graphene oxidation Graphene oxidation is used to create a single layer graphene sheet.

  2. Graphene layers producedOxidation experimental procedure • Sample oxidized at 450 oC for 10 min; • Sample heated at 550 oC for 10 min; • Sample heated at 550 oC for 20 min; Atomic force microscopy (AFM) after each step to see the effects of the oxidation on several graphite platelets AFM use Nanoscope IIIa instrument operating in air.

  3. AFM of graphite platelet • Platelet folds in several surfaces • Nanoparticles on a surface • Surface roughness (RMS) –> flattening; • Height of platelet

  4. AFM cont. • Height decrease from 2.9 nm to 0.7-1.1 nm due to removal of residual material • Monoleyer dips began to appear

  5. AFM cont. • c.11’ – single graphene layer (0.39nm) • 22 – two-layer thickness • d. 11’-Thickness becomes uniform • 22’ – etched substrate surface (SiO2 layer) (0.4nm)

  6. 4th oxidation step • 550 oC for 30 min. • Armchair edge

  7. Electronic properties • Depend on the width; • Edge effects; • Band structure observed by scanning tunnelling microscopy and spectroscopy

  8. Optical properties • Raman spectroscopy: • thickness (layer no) 2D/G; • Disorder (lattice defects) D/G; • Temperature • Sensitive to a single layer

  9. Conclusion • Graphene single layers bring interest in nanoscience • Building blocks in electronic applications; • Graphene transistor • Graphite oxidation paper

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