Home About us Contact
|
Home About us Contact | ||
|
|
||
Semiconductor Structures (semiconductor + structure)
Selected AbstractsLight-Induced Bipolar-Resistance Effect Based on Metal,Oxide,Semiconductor Structures of Ti/SiO2/SiADVANCED MATERIALS, Issue 9 2010Chongqi Yu A novel approach to the control of resistance in a Ti/SiO2/Si structure is demonstrated by use of a laser via a phenomenon referred to as the bipolar-resistance effect (BRE). The most significant features of this BRE are an excellent spatial sensitivity and a large change ratio in resistance as the laser moves along the surface of the structure. [source] Fiber Field-Effect Device Via In Situ Channel CrystallizationADVANCED MATERIALS, Issue 37 2010Sylvain Danto The in situ crystallization of the incorporated amorphous semiconductor within the multimaterial fiber device yields a large decrease in defect density and a concomitant five-order-of-magnitude decrease in resistivity of the novel metal-insulator-crystalline semiconductor structure. Using a post-drawing crystallization process, the first tens-of-meters-long single-fiber field-effect device is demonstrated. This work opens significant opportunities for incorporating higher functionality in functional fibers and fabrics. [source] Nano-floating gate capacitor with SnO2 quantum dots distributed in polyimide dielectricsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2009Dong Uk Lee Abstract Self-assembled SnO2 quantum dots were fabricated by a chemical process between a BPDA-PDA polyamic acid and a Sn film. A nano-floating gate capacitor having metal,insulator,semiconductor structure has been formed on p-type Si substrate with SnO2 quantum dots and dielectric polymer layer. The size and density of fabricated SnO2 quantum dot were about 15 nm and 2.4 × 1011 cm,2, respectively. The electrical properties of the nano-floating gate capacitor have been investigated by measuring capacitance,voltage characteristics. Then, the flat-band voltage shift due to charging of the electron in SnO2 quantum dot was ranged from 1.2 V to 4 V. And the transmission electron microscopy and the optical absorption spectra have been measured to investigate the morphology and absorbance of the SnO2 quantum dots embedded in polyimide. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Manufacturing tolerances of terrestrial concentrator p-on-n GaAs solar cellsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 1 2001Carlos Algora The increasing interest in the manufacturing of terrestrial concentrator GaAs solar cells calls for the need to establish the guidelines, assessments and tolerances of the production process. Accordingly, this paper analyses, for the first time, the tolerances of this process. The influence of the entire solar cell (antireflecting coatings, semiconductor structure and series resistance) is considered. More specifically, the parameters analysed are: the thickness of the double antireflecting coating, window thickness, emitter thickness, base thickness, emitter doping level, base doping level, shadowing factor and specific front contact resistance. The results are presented in the form of iso-efficiency plots as a function of the aforementioned parameters. Therefore, besides the conclusions extracted in this paper, numerous others may be formed according to particular necessities. Copyright © 2001 John Wiley & Sons, Ltd. [source] Localization of excitons in weakly disordered semiconductor structures: A model studyANNALEN DER PHYSIK, Issue 12 2009N. Gögh Abstract Localization of the center-of-mass (com) motion of an exciton in a disordered semiconductor structure is studied theoretically by focusing on nonlinear optical spectroscopy. A one-dimensional tight-binding model with diagonal disorder is applied and the Coulomb interaction is treated consistently. In the ordered situation the center-of-mass momentum (K) selection rule leads to only the lowest transition for K = 0. The break down of the com-K-selection rule produces the well known asymmetric excitonic lines of disordered semiconductors. The coupling between the lowest dominant transition to this modified com-continuum yields Fano-like features in the nonlinear spectra. [source] Capacitive electrolyte,insulator,semiconductor structures functionalised with a polyelectrolyte/enzyme multilayer: New strategy for enhanced field-effect biosensingPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2010Maryam H. Abouzar Abstract A novel strategy for enhanced field-effect biosensing using capacitive electrolyte,insulator,semiconductor (EIS) structures functionalised with pH-responsive weak polyelectrolyte/enzyme or dendrimer/enzyme multilayers is presented. The feasibility of the proposed approach is exemplarily demonstrated by realising a penicillin biosensor based on a capacitive p-Si,SiO2 EIS structure functionalised with a poly(allylamine hydrochloride) (PAH)/penicillinase and a poly(amidoamine) dendrimer/penicillinase multilayer. The developed sensors response to changes in both the local pH value near the gate surface and the charge of macromolecules induced via enzymatic reaction, resulting in a higher sensitivity. For comparison, an EIS penicillin biosensor with adsorptively immobilised penicillinase has been also studied. The highest penicillin sensitivity of 100,mV/dec has been observed for the EIS sensor functionalised with the PAH/penicillinase multilayer. The lower and upper detection limit was around 20,µM and 10,mM, respectively. In addition, an incorporation of enzymes in a multilayer prepared by layer-by-layer technique provides a larger amount of immobilised enzymes per sensor area, reduces enzyme leaching effects and thus, enhances the biosensor lifetime (the loss of penicillin sensitivity after 2,months was 10,12%). [source] X-ray characterization of epi-Ge/Pr2O3/Si(111) layer stacks by pole figures and reciprocal space mappingPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2009Peter Zaumseil Abstract An epi-Ge/Pr2O3/Si(111) layer structure prepared by consecutive steps of epitaxial deposition and annealing is used to demonstrate the possibility of a complex characterization by combination of different X-ray diffraction techniques. Especially pole figure measurements, reciprocal space mapping (RSM) and high resolution (HR) ,/2, scans at selected inclined netplanes were successfully used to determine the in-plane lattice orientation of the layers relative to the substrate, the strain state of all layers and the structural perfection of the epi-Ge film. It was found that the major part of the epi-Ge layer has the same type A stacking orientation as the Si substrate, but about 0.6% is of type B. The Pr2O3 buffer layer exhibits type B only. The strain state of oxide and epi-Ge was determined, and a small difference in the lattice constant of type A and B epi-Ge was found. Microtwins lying in inclined {111} planes were unambiguously identified by pole figure measurements as the dominating structural defects in the epi-Ge layer. They cause a characteristic scattering pattern in reciprocal space maps. The proposed combination of X-ray techniques allows a relatively fast, integral and non-destructive analysis of heteroepitaxial semiconductor oxide semiconductor structures. [source] Cathodoluminescence spectral mapping of III-nitride structuresPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2004R. W. Martin Abstract The application of cathodoluminescence spectral mapping to the characterisation of a range III-nitride semiconductor structures is described. Details are presented of the instrumentation developed to carry out such measurements using an electron probe micro-analyser. The spatial resolution of the luminescence data is ,100 nm. The technique is enhanced by the ability to simultaneously perform X-ray microanalysis and electron imaging. Results are presented from epitaxially laterally overgrown GaN and InGaN/GaN structures using both single-layer SiO2 and multilayer SiO2/ZrO2 masks. Effects of strain and microcavity formation are resolved. Application of the technique to InGaN epilayers shows spatially-dependent shifts in the peak wavelength of the luminescence spectrum which correlate directly with microscopic variations in the indium content. Regions emitting at lower energy and with decreased intensity are shown to have higher InN contents, mirroring equivalent macroscopic observations. Finally the spectral mapping technique is used to analyse the luminescence from micron-scale selectively grown III-N pyramids, indicating possible formation of quantum dots at the sharp tips. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Zero dimensional exciton-polaritonsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2006A. Baas The cover picture from the article [1] shows, in the left parts of the three diagrams, the measured photoluminescence intensity as a function of energy and emission angle for a 3 ,m (left diagram), 9 ,m (middle diagram) and 19 ,m-diameter quasi-circular mesa (right diagram). The white lines are the energy dispersions of 2D polariton modes. For clarity, intensities above 1485 meV have been multiplied by a constant factor, as indicated. The right parts of the diagrams contain intensity plots of the simulated polariton spectral density for cylindrical mesas of the same diameters, yielding very good quantitative agreement of the 0D polariton states in the circular mesas. This confirms the coexistence of 0D and 2D microcavity polaritons in these semiconductor structures. This paper is an invited presentation from the 8th International Workshop on Nonlinear Optics and Excitation Kinetics. Further articles from NOEKS 8 are published in phys. stat. sol. (c) 3, No. 7 (2006). [source] Defect profiles in semiconductor structuresPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2007P. G. Coleman Abstract Variable-energy positron annihilation spectroscopy (VEPAS) has found applications in structural and electronic analysis of thin films and near-surface layers, nanoporous materials, ion implantation, silicon photonics, and vacancy engineering. In all this applied work it is essential that VEPAS is treated as a normal member of the arsenal of spectroscopies available to the semiconductor research community. Examples are presented of how useful insights into current problems in semiconductor physics and technology have been gained by combinations of VEPAS and other techniques such as secondary ion mass spectrometry, transmission electron microscopy, electrical characterization, and optical techniques such as photoluminescence and optically-detected magnetic resonance. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||