Selective nucleation and controlled growth: quantum dots on metal, insulator and semiconductor surfaces

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We have developed hybrid AFM probes with SU-8 polymer body and full platinum and tungsten cantilever and tip. The fabrication process uses surface micromachining of a (100) silicon wafer. The metal (platinum or tungsten) is sputter deposited in oxidation sharpened moulds, giving a final tip sharpness smaller than 20 nm. A SU-8 body is subsequently formed. The release is either done by a wet back-side or dry top-side process. The measured hardness of the tungsten and platinum film values 14.8 GPa and 7.3 GPa

The endeavour to develop nanodevices demands for patterning methods in the nanoscale. To bring nanodevices to the market, there is a need for fast, low-cost replication nanopatterning methods. In addition, an increased flexibility of the nanopatterning methods is important for the engineering of multimaterial and multifunctional nano/micro-electro-mechanical systems (NEMS/MEMS), such as polymer-based electronic and sensor devices, 3D microfluidic systems, and bio-analytical systems. A series of alternative,

We report here on a new method to release functional SU-8 micro-components with embedded and integrated metal electrodes from the surface, based on isotropic SF6 dry etching of a poly-silicon sacrificial layer. This new fast and clean release technique allows a reproducible fabrication of SU-8 structures with integrated metal devices without risk of damage or altering their performance.

We report on the growth and optical properties of dense arrays of single GaAs/AlGaAs quantum dot (QD) heterostructures with pitches as small as 300 nm. The samples were grown by organometallic chemical vapor deposition in dense inverted pyramids on {1 1 1}B GaAs substrate pre-patterned using electron beam lithography and wet chemical etching. The growth conditions such as deoxidation and growth temperatures, growth rates, and V/III ratio, had to be chosen quite differently from those employed with micron-si

The voltage-induced assembly of mercaptosuccinic acid-stabilized Au nanoparticles of 1.5 ± 0.4 nm diameter is investigated at the polarizable water|1,2-dichloroethane interface. Admittance measurements and quasi-elastic laser scattering (QELS) studies reveal that the surface concentration of the nanoparticle at the liquid|liquid boundary is reversibly controlled by the applied bias potential. The electrochemical and optical measurements provide no evidence of irreversible aggregation or deposition of the pa

When AxGa1-xAs layers are grown on V-grooved GaAs substrates by metal organic chemical vapour deposition (MOCVD), a Ga rich vertical quantum well (VQW) appears in the V-groove centre. The width and Ga enrichment of this structure depend on the nominal Al concentration and growth temperature. From EELS linescans and spectrum images, concentration profiles and maps of VQWs are obtained, and a subsequent bandstructure calculation shows up to three confined sublevels in the VQW. Carrier confinement in segments

Spatially resolved photoluminescence spectra of thin GaAs quantum wells are measured by near-field spectroscopy, and two-energy autocorrelation functions of the spectra are derived. We demonstrate distinctly different autocorrelation functions for a 3-nm-thick quantum well grown on a (311)A surface and for quantum wells grown on (100) substrates. The autocorrelation spectra of the (311)A GaAs quantum well are quantitatively described by a statistical disorder model with a single correlation length of 17 nm

Strontium barium niobate thin films have been deposited by pulsed laser deposition on (111)-textured Pt films, p-doped Si(I 00) and Nb doped STO (SrTiO3) single crystals. The deposition parameters were optimized for obtaining phase pure (001)-oriented films from stochiometric targets. The samples were annealed in oxygen to improve top electrode adhesion and reduce oxygen vacancies. The SBN/substrate interfaces were investigated by means of TEM combined with EDAX chemical analysis. Growth on silicon resulted

In the last years, static power converters have become widely used in various applications. They can be found in domestic applications, railways, urban and ship transport, and even in several industrial systems. Some of these applications require a high or medium voltage power supply that is easily adjustable while providing good spectral performances. To overcome the maximum blocking voltage limits of the main power switches, multilevel techniques and other new power conversion topologies have been develop

A novel MEMS technological platform for RF passive components, namely RF MEMS switches, tuneable capacitors and high-Q suspended inductors, is reported. The proposed process employs a metal (Al, AlSi or Cu) as active movable layer and amorphous silicon or polycrystalline silicon as sacrificial layers, providing multi-air-gaps. Various types of substrates like bulk silicon and SOI can be used. Full-dry releasing of suspended beams and membranes is performed with SF_6 or XeF_2, with unrivalled yield/reproduci

AIN is a material used in a wide variety of applications such as electroacoustic devices, blue diodes, IR windows, thermal conductors, metal-insulator-semiconductor structures, integrated circuit packaging, etc. In this work thin piezoelectric AIN polycrystalline films have been grown on Si and SiO2 using rf magnetron sputter deposition in an Ar/N-2 gas mixture. The structural properties of the film have been optimized by varying the deposition parameters, such as process pressure, gas mixture, substrate te

This thesis deals with the development of microfabrication technologies based on photoplastic structuring by lithographic and molding techniques. These technologies, combined with an original releasing method, allow for the simple fabrication of pseudo three-dimensional, soft, photoplastic microstructures with features and shapes that are difficult to obtain with standard micro-machining. The photoplastic material used is the SU-8 photoresist, a material that is used increasingly in the growing field of mic

Selective nucleation and controlled growth: quantum dots on metal, insulator and semiconductor surfaces

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Full tungsten and platinum nanoprobes for electrically conducting scanning probe methods

Advancing towards well-controlled full-wafer nanostencil lithography

Surface microfabricated SU-8 devices with integrated electrodes for scanning probe microscopy

Growth and Optical Characterization of Dense Arrays of Site-Controlled Quantum Dots Grown in Inverted Pyramids

Reversible Voltage-Induced Assembly of Au Nanoparticles at Liquid|Liquid Interfaces

Use of quantitative EELS and cathodoluminescence for study of carrier confinement and diffusion in self organized vertical quantum wells

Near-field autocorrelation spectroscopy of disordered semiconductor quantum wells

Microstructural and electrical properties of (Sr,Ba)Nb2O6 thin films grown by pulsed laser deposition

Convertisseurs multiniveaux asymétriques alimentés par transformateurs multi-secondaires basse-fréquence : réactions au réseau d'alimentation

A novel RF MEMS technological platform

Structural and electroacoustic studies of AIN thin films during low temperature radio frequency sputter deposition

New photoplastic fabrication techniques and devices based on high aspect ratio photoresist