Zinc Diffusion in Gaas and Zinc-Induced Disordering of Gaas Algaas Multiple Quantum-Wells - a Multitechnique Study

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The unique properties of transition metal dichalcogenides provide a versatile platform for scalable, room-temperature quantum devices. Their future commercialization will inevitably depend on the development of heterostructures facilitating charge injection into pre-defined areas of 2D components. We showcase here an innovative approach to accurately characterize electrically active nanoscale regions in multidimensional heterostructures made of WSe₂ layers and GaAs, thin films and in-plane one-dimensional n

Limited-angle electron tomography (ET) aims to reconstruct 3D shapes from 2D projections of transmission electron microscopy (TEM) within a restricted range and number of tilting angles, but it suffers from the missing-edge problem that causes severe reconstruction artefacts. Deep learning approaches have shown promising results in alleviating these artefacts, yet they typically require large high-quality training datasets with known 3D ground truth, which are difficult to obtain in electron microscopy. To

Phase retrieval is a nonlinear inverse problem that arises in a wide range of imaging modalities, from electron microscopy to Fourier ptychography. In particular, the reconstruction is facilitated when the sensing matrix is i.i.d. random, enabling strong theoretical guarantees and efficient reconstruction algorithms. However, its applicability is restricted by excessive computational costs. In this paper, we propose structured random models for phase retrieval, where we emulate a dense random matrix by a ca

An apparatus for observing dynamic systems by time-resolved microscopy has an optical microscope including a cryo stage for receiving a cryo sample and maintaining the cryo sample at a cryogenic temperature, a heating system configured to temporarily heat at least a portion of the cryo sample such that the portion of the cryo sample melts to a liquid state, temporarily resides in the liquid state, and then revitrifies, and an image detector associated with the optical microscope for detecting magnified imag

Perovskite solar cells (PSCs) can reach power conversion efficiencies above 26% through simple fabrication methods, offering key advantages over established photovoltaic technologies. Yet, for PSCs to contribute to the energy transition, their operational stability must be improved. The mixed ionic-electronic conductivity of the metal halide perovskite absorber induces reversible and irreversible performance changes linked to electric field-driven ionic accumulation. The extent to which PSCs are affected by

We have recently introduced a novel approach to time-resolved cryo-electron microscopy (cryo-EM) that affords microsecond time resolution. It involves melting a cryo sample with a laser beam to allow dynamics of the embedded particles to occur. Once the laser beam is switched off, the sample revitrifies within just a few microseconds, trapping the particles in their transient configurations, which can subsequently be imaged to obtain a snap shot of the dynamics at this point in time. While we have previousl

This paper presents an analytical and experimental study of a compact configuration to harvest energy from a rotating gear using piezoelectric microelectromechanical system harvesters. The reported configuration realizes a contact-type frequency up-conversion mechanism in order to generate useful electrical energy. The up-conversion mechanism was achieved using an atomic force microscope (AFM)-like piezoelectric cantilever plucked by the teeth of the rotating gear that could be eventually driven by an oscil

Ion Accoustic Wave (IAW) dynamics are usually simulated assuming an isothermal Boltzmann ﬂuid response of the electrons. It has been shown that results from the Boltzmann model may signiﬁcantly diﬀer from cor- responding ones obtained considering the fully kinetic electron dynamics, in particular wrt. the non-linear instability mechanisms of ﬁnite amplitude IAWs [1]. For ZTe /Ti 10 (Z the ionization degree and Te/i the electron/ion temperature), the positive contribution from trapped electrons to the non- l

In this contribution, we study the increase in metalorganic-low pressure chemical vapor deposited (MO-LPCVD) ZnO thin films conductivity by hydrogen plasma post-treatment. We show that this improvement is linked to defect passivation at grain boundaries, decreasing the electron traps density and resulting in the almost complete suppression of the electron scattering at grain boundaries. For a 2 μm thick non-intentionally doped ZnO layer, electron mobility reaches after treatment values close to 60 cm2V-1s-1

We present results on various post processing techniques to create complex 3-dimensional nanostructures with enhanced capabilities. The starting point for all architectures is a self aligned nanopillar with surrounding circular rim in PMMA. This particular shape is obtained by the energy density distribution of incident and backscattered electrons of e-beam exposure and reflects the dual behavior of PMMA as positive and negative resist. Employing only 1 lithographic step and several batch processing techniq

Recently, the dynamics of atomic distances and orbital charge in graphite has been investigated by ultra-fast electron diffraction, electron energy loss spectroscopy and transient optical absorption. A subtle interplay between structural motions and electronic degrees of freedom was found responsible for several peculiar behaviors like coherent phonon emission, photoinduced diamond formation, and graphene ablation. Here, we calculate ab initio the charge density of graphite, and observe its evolution during

A detailed structural analysis of the surface supported self-assembly of terphenyl-4,4′′-dicarbonitrile molecules (NC−Ph3−CN) linked by Co adatoms on Ag(111) reveals different surface patterns depending on the constraints applied to the system. Without constraints, i.e., sufficient mobility and absence of space limitations at the surface, extended regular honeycomb nanomeshes are formed. On the basis of high-resolution scanning tunneling microscopy images, an atomistic model is derived showing the crystallo

We propose a new measurement technique to investigate the highly focused light used in optical data storage systems named immersion high resolution interference microscopy (HRIM). This system allows three-dimensional (3D) measurements of the amplitude and phase of light fields in a static scheme. In contrast to scanning techniques, HRIM allows the nondestructive investigation penetrating through the optical disc. We investigated the focusing of light in high-definition digital versatile disc (HD DVD) system

GaN/AlN multiple quantum wells (MQWs), designed for intersubband (ISB) absorption in the telecommunication range, are grown by molecular beam epitaxy. We demonstrate that the use of both AlN template and optimized growth temperature allows to reach ISB transition energy in the telecom range, i.e. above 0.8 eV (lambda = 1.55 mu m). Absorption spectra exhibit narrow linewidth (< 50 meV) with a relative energy broadening of 8%. An electro-optical modulator based on electron tunnelling in coupled QWs is then fa

Smart packaging concept has been the driving force for the search of advanced technologies to produce multi-functional micro-scale devices for long years. In this sense, LTCC technology has been recently addressed as the suitable choice for a wide range of applications. In addition to its attractive characteristics for high-frequency applications those have been profited for a long time, it receives a growing attention for sensor applications in the recent years as well. This is due to the easy machinabilit

We develop wear resistant, electrically conducting AFM probes. Here, we describe a new AFM probe made entirely out of tungsten (W). The fabrication involves microfabrication techniques such as surface moulding, thin-film structuring of tungsten and high aspectratio SU-8 patterning. The metallic cantilever and tip are attached to a SU-8 photopolymer body. The free-standing 500-nm-thick cantilevers are obtained by a wafer-through etching. Figure 2 shows a SEM image of the SU-8 body with W cantilevers and a cl

Scanning capacitance microscopy and electrostatic force microscopy have been used to characterize commercial semiconductor devices at various stages of the fabrication process. These methods, combined with conventional atomic force microscopy, allow to visualize qualitatively the oxide thickness, the nature of dopants and the exact position of implanted areas. (C) 2002 Elsevier Science Ltd. All rights reserved.

Irradiated 304 and 316 stainless steel samples were investigated. The steels were neutron irradiated to 1.5 and 7.5 dpa at 550 K. Similar types of steels were irradiated at 550 K with 590 MeV protons in the PIREX facility at PSI, Switzerland. The doses reached in this case were 0.15 and 0.3 dpa. The stress-strain relationships at different temperatures were measured. The irradiation and deformation microstructures were investigated using transmission electron microscopy (TEM). Two modes of deformation were

The temperature-dependent damping of quantum-mechanical interference patterns from surface-state electrons scattering off steps on Ag(111) and Cu(111) has been studied using scanning tunneling microscopy (STM) and spectroscopy in the temperature range 3,5-178 K. The thermal damping of the electron standing waves is described quantitatively within a simple plane-wave model accounting for thermal broadening due to the broadening of the Fermi-Dirac distributions of sample and tip, for beating effects between e

Wide quantum wells, where the energy spacing between the first two energy levels is lower than the energy of the polar optical phonon, could represent the ideal condition to obtain a population inversion and the production of infrared lasers. On the other hand in these quantum wells the efficiency of carrier-carrier scattering is increasing with the width of the well and can produce a relatively quick relaxation of carriers in the first subband. In this work we present a detailed and systematic joint theore

Zinc Diffusion in Gaas and Zinc-Induced Disordering of Gaas Algaas Multiple Quantum-Wells - a Multitechnique Study

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Visualizing nanoscale charge flows in multi-dimensional WSe2/GaAs vertical diodes

Limited-angle tomography reconstruction via projector guided 3D diffusion

Structured Random Models for Phase Retrieval with Optical Diffusers

Microsecond melting and revitrification of cryo samples with a correlative light electron microscopy setup

Device Physics of Ion Migration in Perovskite Solar Cells

Microsecond melting and revitrification of cryo samples with a correlative light-electron microscopy approach

Harvesting Energy From a Rotating Gear Using an AFM-Like MEMS Piezoelectric Frequency Up-Converting Energy Harvester

Reduced Electron Model with Accurate Trapping Effects for Non-Linear Ion Accoustic Waves

Enhanced mobility of hydrogenated MO-LPCVD ZnO contacts for high performances thin film silicon solar cells

Pattern transfer and post processing of complex nanostructures formed by e-beam exposure in PMMA

The interplay between structure and orbitals in the chemical bonding of graphite

Surface-Confined Metal?Organic Nanostructures from Co-Directed Assembly of Linear Terphenyl-dicarbonitrile Linkers on Ag(111)

Amplitude and Phase Measurements of Highly Focused Light in Optical Data Storage Systems

Growth of intersubband GaN/AlGaN heterostructures

Structuration of micro-fluidic devices based on low temperature co-fired ceramic (LTCC) technology

ALL TUNGSTEN AFM CANTILEVER WITH < 40 NANOMETRE PYRAMIDAL TIP

Use of scanning capacitance microscopy for controlling wafer processing

The effects of irradiation and testing temperature on tensile behaviour of stainless steels

Thermal damping of quantum interference patterns of surface-state electrons

Carrier-carrier interaction and fast intersubband scattering in wide GaAs quantum wells