Study Of Metal-Semiconductor Contacts For Enhancing Raman Scattering

Zinc oxide (ZnO) has received renewed attention in recent years due its excitingproperties as a wide band gap semiconductor. ZnO has several advantages over othersemiconductors including the availability of substrates, a room temperature excitonicemission, and an environmentally benign chemistry. ZnO, with its excellentluminescent properties and the ease of growth of its nanostructures, holds promise forthe development of photonic devices. The recent advances in applications of ZnOnanorods are discussed. Although there is an abundance of literature, there has yet tobe an attempt to understand the physical and chemical mechanisms at metal-ZnOinterfaces.In this work, we proposed several model based on metal-semiconductornanocomposites, and employed the metal-semiconductor contacts in these specificmodel for a better understanding of the nature of interfacial charge-transfer process.These models allow for molecular modification of the surface as a probe by means ofsurface-enhanced Raman scattering (SERS) technique.1. These contacts can provide added SERS activity to models. Surface introductionof molecule layer provide a potential roadmap to interfacial charge-transfer of thenature of metal-ZnO contacts. Metal-ZnO contacts have identified it as a primarycharge-transfer resonant responsible for a large enhancement of the Ramanscattering of molecules.2. In addition, we followed changes at the molecule junctions during theconditioning and eventually effect of charge-transfer through molecule-ZnO interfaces. These results demonstrate that the interaction between thesemiconductor bands and molecular energy levels can lead to novel chargebehavior. The typical ZnO-molecule interfacial electron hole recombinationcauses an increase in the CT resonance enhancement of Raman scattering.Molecular adsorption treatment has also yielded a multiphonon resonant Ramanscattering by reducing oxygen defects at the surface of ZnO.3. Deposition of metals on clean and ordered surfaces of ZnO nanorods reveal theimportance that defects play at the metal-ZnO interface. Higher concentrations ofdefects promote charge-transfer.This work not only shows a possibility for further understanding the origin of theSERS mechanism from semiconductor substrates but also for exhibits a situcharacterization technique for probing the photoinduced interface charge-transferprocesses.