Electron doping

Semiconductors (qv) are materials with resistivities between those of conductors and those of insulators (between 10 and 10 H-cm). The electrical properties of a semiconductor determine the hmctional performance of the device. Important electrical properties of semiconductors are resistivity and dielectric constant. The resistivity of a semiconductor can be varied by introducing small amounts of material impurities or dopants. Through proper material doping, electron movement can be precisely controlled, producing hmctions such as rectification, switching, detection, and modulation. 

Host cations are easily oxidized and reduced [transition metals (Fe203, Mn203, etc.)]. In both donor (higher valence) and acceptor (lower valence) doping electronic compensation (donors by electrons and acceptors by holes) will be preferred to structural (vacancies and interstitials) compensation. 

J. Kido and T. Matsumoto, Bright organic electroluminescent devices having a metal doped electron injection layer, Appl. Phys. Lett., 73 2866-2868 (1998). 

Polysilanes are cr-conjugated polymers composed of Si-Si skeletons and organic pendant groups. They are insulators with filled intramolecular valence bands and empty intramolecular conduction bands. However, because of strong cr conjugation, they have rather narrow band gaps of less than 4 eV [24,25] and are converted to conductors by photoexcitation or by doping electron donors or acceptors. Recently they have attracted much attention because of their potential utility as one-dimensional conductors, nonlinear optical materials, and electroluminescent materials [26-28]. 

Doped DNA (by this we mean DNA strands whose electrical charge and electron count have been varied by transfer from electron donors or electron acceptors) can be thought of by analogy to doped electron crystals, but once again the narrow bandwidth and disorder characteristic of DNA make the problem more complex. 

Researchers at the Brookhaven National Laboratory, in applying X-ray techniques to a cerium-doped electron superconductor developed at the University of Tokyo, found that the holes of a hole superconductor... 

Indium nitride is a wide-gap semiconductor with negligible intrinsic carrier concentration and there are no reports of deliberate doping. Electron concentrations, most commonly of order 1020 cm 3, appear independent of growth method and are therefore assumed to be of native defect origin. The presence of... 

The parent material is the antiferromagnetic insulator. By doping electrons or holes to the CUO2 plane from the charge reservoir layer, the CUO2 plane becomes metallic and the superconductivity appears. 

Huang, R Shih P.-L Shu, C.-R Chi, Y and Jen, A. K.-Y. 2009. Highly efficient white polymer light-emitting diodes based on lithium salts doped electron transporting layer. Adv. Mater. 21 361-365. 

Electrochemical doping. Polymers can be doped electronically in an electrochemical cell, such as by immersing the material as an electrode in an organic electrolyte solution (LiC104 in tetrahydrofuran or propylene carbonate, with lithium as a counter electrode) or in aqueous electrolytes (PbS04/Pb02 in sulfuric acid solutions, with lead as a counter electrode). 

V.N. Prigodin and A.J. Epstein, Nature of insulator-metal transition and novel mechanism of charge transport in the metallic state of highly doped electronic polymers. Synth. Met., 125,43 (2002). 

Keywords a -Conjugation Barcode Biosensor Doping Electron beam Hybridization Hydrothermal Light-emitting polymer Nanoscale optical property Nanostructure Optoelectronics... 

Figure 8.10. Example of N-functionalized electropolymerizable pyrrole units leading to pre-doped electronically conducting polymers used for post-electropolymerization incro-poration of pophyrin derivatives.

Doping. Electron-acceptor atoms such as boron or electron-donors such as phosphorus are introduced into the area exposed by the etch process to alter the electrical character of the pure silicon, which is an intrinsic semiconductor. These areas are called p-type (e.g., with boron) or n-type (e.g., with phosphorus) to reflect their particular charge carrier in the conduction process. Repeating the previous steps, i.e., thermal oxidation, masking, etching, and doping operations are repeated several times until the last front-end layer is completed, i.e., all active devices have been formed. 

The reversibility of the electrochemical doping process is of interest for a variety of applications other than batteries. For example, since the visual appearance of polymers such as polypyrrole dramatically change on doping, electronic displays have been made using this polymer Similarly, it is feasible to electrochemically switch a conducting polymer film from states which are transparent to... 

EAR 12] Earmme T., Jenekhe S.A., Solution-processed, alkali metal-salt-doped, electron-transport layers for high-performance phosphorescent organic light-... 

It should be noted that in contrast to classical band theory, the doped electrons/ holes generated in conductive polymers are not fuUy delocalized. The reason for... 

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