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Charge Carrier Concentration (charge + carrier_concentration)
Selected AbstractsCharge Transport Physics of Conjugated Polymer Field-Effect TransistorsADVANCED MATERIALS, Issue 34 2010Henning Sirringhaus Abstract Field-effect transistors based on conjugated polymers are being developed for large-area electronic applications on flexible substrates, but they also provide a very useful tool to probe the charge transport physics of these complex materials. In this review we discuss recent progress in polymer semiconductor materials, which have brought the performance and mobility of polymer devices to levels comparable to that of small-molecule organic semiconductors. These new materials have also enabled deeper insight into the charge transport physics of high-mobility polymer semiconductors gained from experiments with high charge carrier concentration and better molecular-scale understanding of the electronic structure at the semiconductor/dielectric interface. [source] Enhanced Properties of Tin(IV) Oxide Based Materials by Field-Activated SinteringJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2003Oana Scarlat The densification of SnO2 (0.9 mol),Sb2O3 (0.1 mol) solid solution without any additives was studied by conventional and field-activated sintering technique (FAST). FAST sintering achieved a relative density value of 92.4% at 1163 K for 10 min versus 61.3% in conventional sintering at 1273 K for 3 h. An abnormal reduction of the IR transmittance and a semiconductor defect structure with only one donor level in the SnO2 energy gap were noticed in the FAST-sintered as compared with the conventionally sintered Sn0.82Sb0.18O2 solid solution. A high charge carrier concentration (i.e., electronic conduction) was shown in the FAST-sintered sample by conductivity measurements and the negative values of the Seebeck coefficient. [source] Influence of NO2 molecule adsorption on free charge carriers and spin centers in porous siliconPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005E. A. Konstantinova Abstract The effect of nitrogen dioxide (NO2) adsorption on free charge carriers and spin centers in porous silicon has been studied by FTIR and ESR spectroscopy. The silicon dangling bond (Pb1 -center) density rises with increasing NO2 pressure (P) while free charge carrier concentration depends on P nonmonotonically. The experimental results are explained by a microscopic model taking into account both the formation of P,(NO2), donor,acceptor pairs and NO2 -induced oxidation of Si nanocrystal surfaces. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Dual functionality of PTSA as electrolyte and dopant in the electrochemical synthesis of polyaniline, and its effect on electrical propertiesPOLYMER INTERNATIONAL, Issue 7 2007Sambhu Bhadra Abstract The electrochemical synthesis of polyaniline (PAni) powder was carried out from an aqueous solution of 0.15 mol L,1 aniline with varying concentrations of p -toluenesulphonic acid (PTSA) at room temperature. The PAni samples thus obtained were characterized using DC and AC conductivity, dielectric properties, infrared spectroscopy, thermogravimetric analysis, X-ray analysis, scanning electron microscopy and ultraviolet spectroscopy. Results showed that PTSA is acting both as electrolyte and doping agent. With an increase in the PTSA concentration, there is more polaron formation, and this means an increase in charge carrier concentration and mobility. This accounts for the increase in conductivity and improved dielectric properties of the resultant PAni. The polymer was subjected to a heating and cooling cycle. The change in conductivity during the heating cycle is quite different from that during the cooling cycle, indicating some kind of hysteresis phenomenon occurring in the system. Moreover there is a net decrease in room temperature conductivity of PAni when subjected to the heating,cooling cycle. This may be due to the oxidation of PAni and generation of some kind of disorder in the structure of PAni during the heating,cooling process. Copyright © 2007 Society of Chemical Industry [source] Graphene Solution-Gated Field-Effect Transistor Array for Sensing ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Markus Dankerl Abstract Graphene, with its unique combination of physical and electronic properties, holds great promise for biosensor and bioelectronic applications. In this respect, the development of graphene solution-gated field-effect transistor (SGFET) arrays capable of operation in aqueous environments will establish the real potential of graphene in this rapidly emerging field. Here, we report on a facile route for the scalable fabrication of such graphene transistor arrays and provide a comprehensive characterization of their operation in aqueous electrolytes. An on-chip structure for Hall-effect measurements allows the direct determination of charge carrier concentrations and mobilities under electrolyte gate control. The effect of the solution-gate potential on the electronic properties of graphene is explained using a model that considers the microscopic structure of water at the graphene/electrolyte interface. The graphene SGFETs exhibit a high transconductance and correspondingly high sensitivity, together with an effective gate noise as low as tens of ,V. Our study demonstrates that graphene SGFETs, with their facile technology, high transconductance, and low noise promise to far outperform state-of-the-art Si-based devices for biosensor and bioelectronic applications. [source] | ||||||||||