High-Electrical-Conductivity Multilayer Graphene Formed by Layer Exchange with Controlled Thickness and Interlayer

Abstract

The layer exchange technique enables high-quality multilayer graphene (MLG) on arbitrary substrates, which is a key to combining advanced electronic devices with carbon materials. We synthesize uniform MLG layers of various thicknesses, t, ranging from 5 nm to 200 nm using Ni-induced layer exchange at 800 °C. Raman and transmission electron microscopy studies show the crystal quality of MLG is relatively low for t ≤ 20 nm and dramatically improves for t ≥ 50 nm when we prepare a diffusion controlling Al2O3 interlayer between the C and Ni layers. Hall effect measurements reveal the carrier mobility for t = 50 nm is 550 cm2/Vs, which is the highest Hall mobility in MLG directly formed on an insulator. The electrical conductivity (2700 S/cm) also exceeds a highly oriented pyrolytic graphite synthesized at 3000 °C or higher. Synthesis technology of MLG with a wide range of thicknesses will enable exploration of extensive device applications of carbon materials.

Semi-transparent graphite films growth on Ni and their double-sided polymer-free transfer

“…The electron carrier concentration, mobility, and electrical conductivity values were 1.6 × 10 20 cm −3 , 220 cm 2 V −1 S −1 and 2000 S cm −1 , respectively. The mobility and conductivity values for our NGF were similar to natural graphite 2 and higher than commercially available highly-oriented pyrolytic graphite (produced at 3000 °C) 29 . The electron carrier concentration value observed was two orders of magnitude higher than the carrier concentration value (7.25 × 10 18 cm −3 ) of recently reported micrometre-thick graphite films produced using high-temperature (3200 °C) of polyimide sheets 20 .…”

“…Catalytic chemical vapour deposition (CVD) is a known method to produce graphene and ultrathin graphite films (< 10 nm) with high structural quality and at reasonable costs [21][22][23][24][25][26][27] . However, in comparison with the graphene and ultrathin-graphite film growth 28 , the large-area growth and/or applications of NGF using CVD remain less explored 11,13,[29][30][31][32][33] .…”

Pairing transition in a double layer with interlayer Coulomb repulsion

“…The role of the layered structures might be important for physical systems ranging from high-T c superconductors [1] to new quantum phases in twisted bilayers with a "magic angle" [2,3]. Another direction of recent research is associated with multilayer graphene [4] and transition metal dichalcogenide multilayers [5], where an anomalous giant magnetoresistance [6], superconductivity [7], and the formation of exciton condensates [8][9][10][11][12][13] have been discussed and observed. Other interesting effects in layered systems are based on the application of an external magnetic field.…”

Impact of Amorphous-C/Ni Multilayers on Ni-Induced Layer Exchange for Multilayer Graphene on Insulators

“…The insertion of an AlO x interlayer between the a-C/Ni multilayer and Ni will further improve the crystal quality of MLG. 30,32…”

“…Recently, we developed metal-induced layer exchange (MILE) of a-C. 28−32 In particular, MILE using Ni enabled us to synthesize uniform MLG at low temperature with a wide range of thicknesses. 29,32 Higashi et al reported the effects of an a-Ge/Au multilayer structure on the layer exchange between Au and Ge. 33,34 The grain size of the resulting Ge layer was significantly improved by using the multilayer structure.…”