Adsorbate Formation/Removal and Plasma‐Induced Evolution of Defects in Graphitic Materials

Abstract

The preparation of adsorbate‐free graphene with well‐defined layer numbers is a current challenge in materials and surface science and required to fabricate graphene‐based nanodevices, such as used in nanoelectromechanical systems. One strategy to tailor the layer number is oxygen‐plasma treatment of few‐layer graphene/graphite flakes. However, when graphitic materials are stored in air under ambient conditions, it is almost inevitable that adsorbates deposit on their surfaces. When precisely removing individual graphene layers from graphitic flakes by oxygen‐plasma treatment, the amount and type of adsorbates strongly affect the required plasma‐treatment process and duration. To examine the removal/etching mechanism involved in removing such layers, few‐layer graphene/graphite flakes, with areas of different layer numbers, are stored in ambient air and stepwise exposed to oxygen plasma in a shielded configuration. The flakes are then successively analyzed by multifrequency atomic force microscopy together with Raman spectroscopy, focusing on etching rate, and adsorbate and defect evolution. Combined in‐plane and out‐of‐plane tip–adsorbate–substrate interaction analysis facilitates discrimination of different types of adsorbates (water, polycyclic aromatic hydrocarbons, and linear alkanes) and their formation with time. The results demonstrate the potential regarding the development of an efficient method for cleaning of graphitic surfaces and ablation of individual graphene layers.

Intelligent Materials and Nanomaterials Improving Physical Properties and Control Oriented on Electronic Implementations

“…The advanced manufacturing approaches include different versatile techniques (see Table 1), such as 3D printing [6][7][8][9][10][11][12][13][14][15], 4D printing [16][17][18][19][20] (3D printing adding the time variable), innovative materials to be processed in actual industrial manufacturing processes [21][22][23][24][25][26][27][28], laser manufacturing [29][30][31][32][33][34][35][36][37], pulsed spray techniques [38][39][40][41][42][43], electrospinning techniques [44][45][46], and plasma treatments [47][48][49][50]. In Figure 3 are illustrated some graphical elements of the above-mentioned topics.…”

“…Finally, plasma treatment [47][48][49][50] is used to change the material's surface morphology and properties. For this application, AI could indicate the local regions to treat, gaining wettability or bio-functionalization properties or maintaining the metallic surface characteristics over time (including cleaning actions, refreshing the surface properties).…”

“…Cleaning of graphitic surfaces and precise ablation of individual graphene layers [50] AI procedure cleaning advanced material (plasma cleaning over time)…”