Metal , hole injection efficiency into

Even when the energetic requirements for electron transfer are satisfied, some oxidants with sufficiently positive electrochemical potentials, particularly H2O2, can exhibit poor hole injection kinetics into bare Si. Hole injection can be efficiently catalyzed by the presence of a metal, which can affect reactivity in two ways. The first is simply that since it is a metal, it provides state density from E f all the way down to the valence band maximum. In effect, the metal can short-circuit the connection between the oxidant and the valence band. Second, the metal can act electrocatalytically to enhance either electrochemical or chemical steps in the redox reactions required to achieve etching. Thus, metals such as Au and Pt both can act as electron/hole conduits, but R is particularly effective at electrocatalytically enhancing reactions of H, H2O, H2O2, and O2. 

An important issue for the performance of an organic electronic device like an OFET is the injection of charge carriers, electrons or holes, from the electrode into the organic material. In case of the commonly used metal electrodes an efficient electron injection is possible only if the Fermi level of the metal and the energy of the lowest unoccupied molecular orbital (LUMO) of the organic material differs by a small amount only. A similar statement applies for hole injection, in this case the position of the highest occupied molecular orbital (HOMO) has to match with the position of the Fermi level. When noble metals, in particular Au, are being used for an electrode one may naively assume... 

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