A planar large sieve and sparsity of time-frequency representations

With the aim of measuring the sparsity of a real signal, Donoho and Logan introduced the concept of maximum Nyquist density, and used it to extend Bombieri's principle of the large sieve to bandlimited functions. This led to several recovery algorithms based on the minimization of the $L_{1}$-norm. In this paper we introduce the concept of {\ planar maximum} Nyquist density, which measures the sparsity of the time-frequency distribution of a function. We obtain a planar large sieve principle which applies to time-frequency representations with a gaussian window, or equivalently, to Fock spaces, $\mathcal{F}_{1}\left( \mathbb{C}\right)$, allowing for perfect recovery of the short-Fourier transform (STFT) of functions in the modulation space $M_{1}$ (also known as Feichtinger's algebra $S_{0}$) corrupted by sparse noise and for approximation of missing STFT data in $M_{1}$, by $L_{1}$-minimization

The 'gated-diode' configuration in MOSFET's, a sensitive tool for characterizing hot-carrier degradation

This paper describes a new measurement technique, the forward gated-diode current characterized at low drain voltages to be applied in MOSFET's for investigating hot-carrier stress-induced defects at high spatial resolution. The generation/recombination current in the drain-to-substrate diode as a function of gate voltage, combined with two-dimensional numerical simulation, provides a sensitive tool for detecting the spatial distribution and density of interface defects. In the case of strong accumulation, additional information is obtained from interband tunneling processes occurring via interface defects. The various mechanisms for generating interface defects and fixed charges at variable stress conditions are discussed, showing that information complementary to that available from other methods is obtaine

Memristives Schaltverhalten in selbst-assemblierten Nanopartikel-Systemen

In this work, the self-assembly of functional nanoparticle composites towards integration into future three-dimensional electronic circuitry was investigated. Using complementary surface-functionalization of metal and semiconductor nanoparticles, self-assembly of heterogeneous nanoparticle agglomerates in dispersion and the formation of nanoparticle arrays on oxide surfaces was shown. Electrical characterization of these systems yielded pronounced non-volatile bipolar memristive switching and threshold switching behavior, respectively.In dieser Arbeit wurde die Selbstassemblierung funktionaler Nanopartikelsysteme in Richtung der Integration in zukünftig dreidimensionale elektronische Schaltkreise untersucht. Durch komplementäre Oberflächenfunktionalisierung von Metall- und Halbleiternanopartikeln wurde die Selbstassemblierung von heterogenen Nanopartikel-Agglomeraten in Lösung und die regelmäßige Anordnung von Nanopartikeln auf Oxidoberflächen gezeigt. Die elektrische Charakterisierung dieser Systeme zeigte jeweils ausgeprägtes nicht-volatiles, bipolares memristives Schaltverhalten und Schwellspannungs-Schaltverhalten

Hot-carrier-induced deep-level defects from gated-diode measurements on MOSFETs

The reverse-bias current in the gated-diode configuration of hot-carrier degraded MOS devices was measured. It is shown that interface defects created by the degradation contribute predominantly to the generation current. The spatial distribution of the deep-level defects was obtained by means of device simulation

Concentration estimates for band-limited spherical harmonics expansions via the large sieve principle

We study a concentration problem on the unit sphere $\mathbb{S}^2$ for band-limited spherical harmonics expansions using large sieve methods. We derive upper bounds for concentration in terms of the maximum Nyquist density. Our proof uses estimates of the spherical harmonics coefficients of certain zonal filters. We also demonstrate an analogue of the classical large sieve inequality for spherical harmonics expansions