Electrode chemical vapor deposition

The radio-frequency glow-discharge method [30-34] has been the most used method in the study of a-C H films. In this chapter, it is referred to as RFPECVD (radio frequency plasma enhanced chemical vapor deposition). Film deposition by RFPECVD is usually performed in a parallel-plate reactor, as shown in Figure 1. The plasma discharge is established between an RF-powered electrode and the other one, which is maintained at ground potential. The hydrocarbon gas or vapor is fed at a controlled flow to the reactor, which is previously evacuated to background pressures below lO"" Torr. The RF power is fed to the substrate electrode... 

This is comparable to or slightly higher than the values reported for single crystal (11) and polycrystalline Ti02 (12), and much higher than those for the TiC>2 film electrode prepared by other methods such as chemical vapor deposition (13) and oxidation (14) and anodization (15) of Ti metal. The high efficiency of the dip-coated Ti(>2 film may be attributed to the porous nature of the film as described below. 

A schematic view of the cold cathode fabrication process is shown in Fig. 10.18. The cold cathode is fabricated by low pressure chemical vapor deposition (LPCVD) of 1.5 pm of non-doped polysilicon on a silicon wafer or a metallized glass substrate. The topmost micrometer of polysilicon is then anodized (10 mA cnT2, 30 s) in ethanoic HF under illumination. This results in a porous layer with inclusions of larger silicon crystallites, due to faster pore formation along grain boundaries. After anodization the porous layer is oxidized (700 °C, 60 min) and a semi-transparent (10 nm) gold film is deposited as a top electrode. 

Chemical vapor deposition [37,38], and thermal or anodic oxidation of Ti substrates [39,40,41] have been used to prepare polycrystalline thin films of Ti02. For example, thin films of Ti02 prepared by anodic oxidation of Ti, followed by electrodeposition of In20s from 0.5 M 102(504)3 show enhanced optical absorption up to 500 nm [42] with the In203 modified electrode showing enhanced photocurrent and photovoltage partially due to the low electrical resistance (10 Q) and reduced overvoltage of the photoanode. 

Fig. 27 Supercapacitor study using graphene electrodes (5 mg each), (a) Cyclic voltammogram of chemical vapor deposited graphene (CG) nanodiamond derived graphene (NG) and exfoliated graphene (EG), (b) Evolution of specific capacitance vs scan rate. (Reprinted with permission Ifom [243])...

Wu JB, Becerril HA, Bao ZN, Liu ZF, Chen YS, Penmans P (2008) Organic solar cells with solution-processed graphene transparent electrodes. Appl Phys Lett 92 263302 De Arco LG, Zhang Y, Schlenker CW, Ryu K, Thompson ME, Zhou CW (2010) Continuous, highly flexible, and transparent graphene films by chemical vapor deposition for organic photovoltaics. Acs Nano 4 2865... 

Boron-doped chemical-vapor-deposited diamond is an exceptionally inert carbon electrode with a very wide potential window and very low voltammetric background current. [A. E. Fischer, Y. Show, and G. M. Swain, Electrochemical Performance of Diamond Thin-Film Electrodes from Different Commercial Sources, Anal. Chem. 2004, 76, 2553.]... 

Several other varieties of semiconducting electrodes have been produced by chemical vapor deposition, as noted earlier, including films of Ti02 on Ti [69], Ti02 on plastic substrates [71], and other materials, such as Fe203 and Sn02 films [11]. Most of these other electrodes have been tested as electrodes for use in photoelectrochemically induced water splitting and have not found conventional electroanalytical utility. 

Generally, a carbon nanotube FET device is constructed by a substrate (gate), two microelectrodes (source and drain), and bridging material between the electrodes, which is typically an individual SWNT or a SWNT network. A SWNT FET is usually fabricated by casting a dispersion of bulk SWNTs or directly growing nanotubes on the substrate by chemical vapor deposition (C VD) either before or after the electrodes are patterned.64 Due to the diffusive electron transport properties of semiconducting SWNTs, the current flow in SWNT FET is extremely sensitive to the substance adsorption or other related events on which the sensing is based. 

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