Transfer-Free Layered Graphene on Silica via Segregation through a Nickel Film for Electronic Applications

Abstract

Transfer-free graphene growth via annealing-induced carbon segregation was investigated on a series of carbon/metal/silica layered samples prepared by sequential deposition of Ni from evaporation of Ni and amorphous carbon thin layers from carbon fiber threads on different silica substrates and further thermal treatments with different annealing times, in an attempt to clarify the evolution of carbon formation and its structural variation along with the segregation procedure. Raman and X-ray photoelectron spectroscopies were applied to analyze the microstructure and chemical composition of the generated graphene layer and the carbon microstructure in the depth direction of the metal layer with the aid of Ar-ion etching. The results revealed the annealing-time dependence of the generated graphene quality, possibly because of the competition between carbon diffusion and metal carbide formation/decomposition during annealing. Few-layer stacked graphene sheets with lower defect concentration and larger crystalline size could be grown with increasing annealing time (<1.5 h), while further extending the annealing time resulted in the pronounced formation of amorphous carbon. Similar results were obtained on different types of silica substrates, revealing that growth of graphene was conspicuously independent of the type of the silica substrate, despite a slight difference in the obtained graphene quality owing to a difference in the lattice microstructure and the surface defect. The in-depth understanding of the mechanism of graphitization helps further development of direct growth of high-quality graphene on insulating substrates for applications in electronic devices.

Ni Single Atom Decorated Porous Hollow Carbon Nanosphere‐Based Electrodes for High Performance Symmetric Solid‐State Supercapacitors

“…The peak in the range of 287.5–288.0 eV is attributed to the C−O/C−OH/C=N bond [46,47] and 289.0–291.0 eV to the C−O−C bond [48] . Another weak intensity peak could be located at around 282.7 eV for Ni‐1.0@N@HCN‐Ar and Ni‐2.0@N@HCN‐Ar (Figures 3a and S11a); it can be assigned to the C−Ni bond thereby supporting the presence of nickel atom in the carbon framework [49] . This peak could not be found for Ni‐0.5@N@HCN‐Ar (Figure S10a), where the amount of Ni‐doping is very less.…”

“…[48] Another weak intensity peak could be located at around 282.7 eV for Ni-1.0@N@HCN-Ar and Ni-2.0@N@HCN-Ar (Figures 3a and S11a); it can be assigned to the CÀ Ni bond thereby supporting the presence of nickel atom in the carbon framework. [49] This peak could not be found for Ni-0.5@N@HCN-Ar (Figure S10a), where the amount of Ni-doping is very less. For Ni-1.0@N@carbon-Ar, the contents of sp 3 and sp 2 carbons are calculated to be 63 % and 20 %, respectively, which suggests that a significant amount of graphitic carbon is distributed in the amorphous carbon matrix.…”

Resistive Switching Crossbar Arrays Based on Layered Materials

“…[155] Transfer-free LMs and electronics were also reported, [156][157][158] however, the use of low (300 °C [143] ) temperature results in LMs with lattice distortions, missing bonds, interstitials, and amorphous regions, resulting in worse materials properties. [156][157][158] Waferscale ultraclean and wrinkle-free transfer processes were developed. [159][160][161] The effect of wrinkles and contaminants on MIMlike RS devices is not as severe as in other devices, such as field-effect transistors (FETs), since, unlike FETs (in which the current flows homogeneously in-plane), the out-of-plane currents driven by RS devices flow only across the most conductive spots.…”

“…These processes introduce contamination into the LM, either from the substrate (10 13 to 10 15 Cu atoms cm −2[ 132 ] ), or scaffold (poly(methyl methacrylate) [ 123 ] ), and can produce cracks (especially in monolayer (1L)‐LMs), wrinkles, and folds. [ 155 ] Transfer‐free LMs and electronics were also reported, [ 156–158 ] however, the use of low (300 °C [ 143 ] ) temperature results in LMs with lattice distortions, missing bonds, interstitials, and amorphous regions, resulting in worse materials properties. [ 156–158 ] Wafer‐scale ultraclean and wrinkle‐free transfer processes were developed.…”

Two-Step Thermal Transformation of Multilayer Graphene Using Polymeric Carbon Source Assisted by Physical Vapor Deposited Copper

“…Compared with gaseous carbon sources [ 19 ], which have high overall costs and storage and transportation risks, solid carbon sources are commonly preferred for their inexpensive availability and controllable structural design [ 20 , 21 ]. Solid carbon sources, such as arc-deposited amorphous carbon [ 22 , 23 , 24 ], diamond [ 14 ], graphite powder [ 25 , 26 ], silicon carbide [ 27 ], and small-molecule organic matter [ 28 , 29 ], combined with specific structural designs and metal catalysts have been used to obtain transfer-free graphene with different numbers of layers and for different application scenarios. Self-assembled monolayers (SAMs) with different molecular structures and chemical compositions can be used to prepare transfer-free graphene with different layer numbers and structures on a variety of dielectric substrates [ 30 , 31 ], but the physical performance of the obtained graphene is somewhat disturbed due to the presence of intrinsic heteroatoms such as silicon.…”