Selective Atomic Layer Deposition of Metals on Graphene for Transparent Conducting Electrode Application.

Although graphene has considerable potential as a next-generation transparent conducting electrode (TCE) material owing to its excellent optical transparency and flexibility, its electrical properties require further improvement for industrial application. This study reports a pathway of doping graphene by selective atomic layer deposition (ALD) of metals to elevate the electrical conductivity of graphene. Introduction of a novel Pt precursor [dimethyl(,-dimethyl-3-butene-1-amine-)platinum(II); CHNPt; DDAP] facilitates a low-temperature (165 °C) process.

Electrical properties of graphene/InO bilayer with remarkable uniformity as transparent conducting electrode.

A graphene/InO bilayer (termed as GI-bilayer) is proposed as a transparent conducting electrode with remarkably improved areal-uniformity. To fabricate this new structure, an InO layer with a thickness of less than 50 nm was grown by atomic layer deposition and then a graphene layer was grown by chemical vapor deposition and subsequently transferred onto the as-grown InO layer. Electrical and optical properties of the GI-bilayer were systematically studied to verify effects of the underlying InO layer.

Self-assembly and continuous growth of hexagonal graphene flakes on liquid Cu.

Graphene growth on liquid Cu has received great interest, owing to the self-assembly behavior of hexagonal graphene flakes with aligned orientation and to the possibility of forming a single grain of graphene through a commensurate growth of these graphene flakes. Here, we propose and demonstrate a two-step growth process which allows the formation of self-assembled, completely continuous graphene on liquid Cu. After the formation of full coverage on the liquid Cu, grain boundaries were revealed via selective hydrogen etching and the original grain boundaries were clearly resolved.

Single-step formation of a graphene-metal hybrid transparent and electrically conductive film.

We report here a rapid (10 s of heating) graphene growth method that can be carried out on any desired substrate, including an insulator, thus negating the need for the transfer from the metal substrate. This technique is based on metal-induced crystallization of amorphous carbon (a-C) to graphene, and involves an ultra-thin metal layer that is less than 10 nm in thickness. Rapid annealing of a bilayer of a-C and metal deposited on the surface leads to the formation of graphene film, and to subsequent breaking-up of the thin metal layer underneath the film, thus resulting in the formation of a graphene–metal hybrid film which is both transparent and electrically conducting.

Gold microshell tip for in situ electrochemical Raman spectroscopy.

Tip fabrication by a new strategy is proposed for simultaneous acquisition of electrochemical (EC) signals from an ultramicroelectrode and spectroscopic information from surface-enhanced Raman scattering (SERS). The EC-SERS tip is prepared by carefully tuning a SERS-active gold microshell to maximize Raman scattering, mechanically attaching it to the end of a micropipet, and electrically connecting it to a ruthenium inner layer through electroless deposition.

Controlling spatial density and size of nanocrystals by two-step atomic layer deposition.

Two-step atomic layer deposition (ALD) is proposed in order to control both the spatial density and size of nanocrystals (NCs) via modulation of the nucleation rate during deposition. In this process, two different deposition conditions are sequentially used: a high nucleation rate condition for the formation of high density NCs and a low nucleation rate condition with a slow growth rate for the subsequent growth of pre-formed NCs. To control the nucleation rate of Ru during ALD, pulsing time and carrier flow rate of the Ru precursor are varied.

Sub-10-nm nanochannels by self-sealing and self-limiting atomic layer deposition.

We report on a novel fabrication method of a nanochannel ionic field effect transistor (IFET) structure with sub-10-nm dimensions. A self-sealing and self-limiting atomic layer deposition (ALD) facilitates the fabrication of lateral type nanochannels smaller than the e-beam or optical lithographic limits. Using highly conformal ALD film structures, including TiO(2), TiO(2)/TiN, and Al(2)O(3)/Ru, we have fabricated lateral sub-10-nm nanochannels with good control over channel diameter.