Electric field reduced charging energies and two-electron bound excited states of single donors in silicon

We present atomistic simulations of the D0 to D- charging energies of a gated donor in silicon as a function of applied fields and donor depths and find good agreement with experimental measure- ments. A self-consistent field large-scale tight-binding method is used to compute the D- binding energies with a domain of over 1.4 million atoms, taking into account the full bandstructure of the host, applied fields, and interfaces. An applied field pulls the loosely bound D- electron towards the interface and reduces the charging energy significantly below the bulk values. This enables formation of bound excited D-states in these gated donors, in contrast to bulk donors. A detailed quantitative comparison of the charging energies with transport spectroscopy measurements with multiple samples of arsenic donors in ultra-scaled FinFETs validates the model results and provides physical insights. We also report measured D-data showing for the first time the presence of bound D-excited states under applied fields

APEX status pt.1: instrument development and performance

ESA APEX (Airborne Prism EXperiment) is a project for the realisation of an airborne dispersive pushbroom imaging spectrometer, a dedicated data Processing and Archiving Facility (PAF, hosted at VITO) and a Calibration Home Base (CHB, hosted at DLR) for instrument calibration operation. It has been developed by a joint Swiss-Belgian consortium. The APEX instrument is facing its finalisation phase undergoing intense experimental activities in view of its validation and performance assessment. Environmental tests were executed to simulate flight environment conditions. The first APEX airborne campaign has been held in June 2009 covering a variety of water targets over Switzerland and Belgium. Extensive pre- and postflight characterisation and calibration campaigns were accomplished. Instrument data evaluation, performance analysis and optimisation of the data processing schemes adopted have followed. This paper outlines the activities performed and presents the first products achieved

Evaluation of the atmospheric correction procedure for the APEX level 2/3 processor

The Airborne Prism Experiment (APEX) is a hyperspectral instrument built in a Swiss - Belgian collaboration within the ESA-PRODEX program [1]. It aims at highest possible accuracy of its delivered surface reflectance image data products. The atmospheric correction of hyperspectral imagery is a critical element of a complete processing chain towards unbiased reflectance and for the creation of higher level products. As the first data of APEX is expected to become available in 2009, an appropriate processing chain for higher level processing needs to be defined and evaluated. Standard products have been identified in all application fields of hyperspectral imaging, i.e., geology, vegetation, cryosphere, limnology and atmosphere. They are being implemented at the APEX science center [2]. The according processing procedures rely on data of well-defined processing states which range from calibrated at-sensor radiance to(bihemispherical) spectral albedo. In this paper, the atmospheric processing which is implemented as part of the automated data processing chain for level 2 in the APEX processing and archiving facility (PAF) [3] is evaluated together with the ATCOR-4 atmospheric correction program [4],[5]. The evaluation is done regarding flexibility, reflectance output accuracy and processing efficiency. Two test data sets are taken for this purpose: a well-documented set of HYMAP data [6] and a high resolution HYSPEX data set [7]. Both data sets exhibit areas of overlap, which are taken for self-contained analysis of the atmospheric correction procedure. The accuracy tests include plausibility checks on selected regions of interest including a variety of known surfaces in the imagery. As some of the observed effects are related to BRDF differences, the results also give an indication for the inaccuracy related to these reflectance anisotropies. Speed measurements of the processing are then compared to the demand for operational processing of series of data acquisition. Further comparison information is drawn from the by-products of atmospheric correction such as water vapor distribution maps. The study shows performance and limitations of atmospheric correction using the state-of-the-art technology, which are mainly found in the field of BRDF effects. This points towards improvements to be implemented in course of the further development of the higher level processing chain for the APEX sensor

Schottky-Barrier height lowering by an increase of the substrate doping in PtSi Schottky barrier source/drain FETs

In this letter, the Schottky-barrier height (SBH) lowering in Pt silicide/n-Si junctions and its implications to Schottky-barrier source/drain p-field-effect transistors (p-SBFETs) are studied experimentally and numerically. We demonstrate that the increase of the n-Si substrate doping is responsible for a larger hole SBH lowering through an image-force mechanism, which leads to a substantial gain of the drive current in the long-channel bulk p-SBFETs. Numerical simulations. show that the channel doping concentration is also critical for short-channel p/n-silicon-on-insulator SBFET performance

Diethyl- and di-n-butyltin(IV) 3-amino-4-methylbenzoates: synthesis, spectroscopic characterization and in vitro antitumour activity

info:eu-repo/semantics/publishe

13C-119Sn Correlation NMR in solution and solid-state CP/MAS NMR of bis(tributylstannyl(IV))O-5,6-isopropylidene-l-(+)-ascorbate

Various NMR correlation techniques, H-1-C-13 HMQC, H-1-C-13 HMBC, H-1-Sn-119 HMQC with gradient enhancement, and C-13-Sn-119 HMQC, enabled a. full resonance assignment and the solution structure elucidation of bis(tributylstannyl(IV)) L-(+)-ascorbate (1) and O-5,6-isopropylidene-L-(+)-ascorbate (2) in deuteriochloroform. Double heteronuclear C-13-Sn-119 HMQC spectroscopy appeared indispensable for discriminating between (2)J(C-13-O-Sn-119) and (3)J(C-13=C-O-Sn-119) coupling pathways involving quaternary carbon atoms and provided useful information about the relative magnitudes of (2)J(C-13-Sn-119) and (3)J(C-13-Sn-119) coupling constants, as they turned out to have an uncommon coupling size sequence. While the tin atoms in compounds I and 2 are four-coordinate in solution, Sn-117 CP/MAS NMR reveals that compound 2 has one four-coordinate and one five-coordinate tin atom in the solid state

Formation of poly(2,5-dibutoxy-1,4-phenylenevinylene) at room temperature in CHCl3 catalyzed by CHCl3 photoproducts

A convenient, mild prepn. of poly(2,5-dibutoxy-1,4-phenylenevinylene) (I) using a modified precursor route is reported. The conversion of the methoxy pendent precursor polymer into its conjugated form is performed in chloroform by the elimination of methanol at room temp., yielding I as a red soln. The elimination is catalyzed by the acid photoproducts of chloroform. [on SciFinder (R)