Sequential Infiltration Synthesis of AlO in PMMA Thin Films: Temperature Investigation by Operando Spectroscopic Ellipsometry.

Sequential infiltration synthesis (SIS) is a scalable and valuable technique for the synthesis of organic-inorganic materials with several potential applications at the industrial level. Despite the increasing interest for this technique, a clear picture of the fundamental physicochemical phenomena governing the SIS process is still missing. In this work, infiltration of AlO into thin poly(methyl methacrylate) (PMMA) films using trimethyl aluminum (TMA) and HO as precursors is investigated by operando dynamic spectroscopic ellipsometry (SE) analysis.

BiTeSe and SbTe heterostructure based photodetectors with high responsivity and broadband photoresponse: experimental and theoretical analysis.

Topological insulators have emerged as one of the most promising candidates for the fabrication of novel electronic and optoelectronic devices due to the unique properties of nontrivial Dirac cones on the surface and a narrow bandgap in the bulk. In this work, the SbTe and BiTeSe materials, and their heterostructure are fabricated by metal-organic chemical vapour deposition and evaporation techniques. Photodetection of these materials and their heterostructure shows that they detect light in a broadband range of 600 to 1100 nm with maximum photoresponse of SbTe, BiTeSe and SbTe/BiTeSe at 1100, 1000, and 1000 nm, respectively.

Sequential Infiltration Synthesis of AlO in Biodegradable Polybutylene Succinate: Characterization of the Infiltration Mechanism.

The introduction of inorganic materials into biopolymers has been envisioned as a viable option to modify the optical and structural properties of these polymers and promote their exploitation in different application fields. In this work, the growth of AlO in freestanding ∼30-μm-thick poly(butylene succinate) (PBS) films by sequential infiltration (SIS) at 70 °C via trimethylaluminum (TMA) and HO precursors was investigated for the first time. The incorporation of AlO into the PBS matrix was clearly demonstrated by XPS analysis and SEM-EDX cross-sectional images showing a homogeneous AlO distribution inside the PBS films.

Interface Analysis of MOCVD Grown GeTe/SbTe and Ge-Rich Ge-Sb-Te/SbTe Core-Shell Nanowires.

Controlling material thickness and element interdiffusion at the interface is crucial for many applications of core-shell nanowires. Herein, we report the thickness-controlled and conformal growth of a SbTe shell over GeTe and Ge-rich Ge-Sb-Te core nanowires synthesized via metal-organic chemical vapor deposition (MOCVD), catalyzed by the Vapor-Liquid-Solid (VLS) mechanism. The thickness of the SbTe shell could be adjusted by controlling the growth time without altering the nanowire morphology.

Improving HfO-Based Resistive Switching Devices by Inserting a TaO Thin Film via Engineered In Situ Oxidation.

Resistive switching (RS) devices with binary and analogue operation are expected to play a key role in the hardware implementation of artificial neural networks. However, state of the art RS devices based on binary oxides (e.g.

Phase Change Ge-Rich Ge-Sb-Te/SbTe Core-Shell Nanowires by Metal Organic Chemical Vapor Deposition.

Ge-rich Ge-Sb-Te compounds are attractive materials for future phase change memories due to their greater crystallization temperature as it provides a wide range of applications. Herein, we report the self-assembled Ge-rich Ge-Sb-Te/SbTe core-shell nanowires grown by metal-organic chemical vapor deposition. The core Ge-rich Ge-Sb-Te nanowires were self-assembled through the vapor-liquid-solid mechanism, catalyzed by Au nanoparticles on Si (100) and SiO/Si substrates; conformal overgrowth of the SbTe shell was subsequently performed at room temperature to realize the core-shell heterostructures.

Epitaxial and large area SbTe thin films on silicon by MOCVD.

Antimony telluride (SbTe) thin films were prepared by a room temperature Metal-Organic Chemical Vapor Deposition (MOCVD) process using antimony chloride (SbCl) and bis(trimethylsilyl)telluride (Te(SiMe)) as precursors. Pre-growth and post-growth treatments were found to be pivotal in favoring out-of-plane and in-plane alignment of the crystallites composing the films. A comprehensive suite of characterization techniques were used to evaluate their composition, surface roughness, as well as to assess their morphology, crystallinity, and structural features, revealing that a quick post-growth annealing triggers the formation of epitaxial-quality SbTe films on Si(111).

High-Density Sb Te Nanopillars Arrays by Templated, Bottom-Up MOCVD Growth.

Sb Te exhibits several technologically relevant properties, such as high thermoelectric efficiency, topological insulator character, and phase change memory behavior. Improved performances are observed and novel effects are predicted for this and other chalcogenide alloys when synthetized in the form of high-aspect-ratio nanostructures. The ability to grow chalcogenide nanowires and nanopillars (NPs) with high crystal quality in a controlled fashion, in terms of their size and position, can boost the realization of novel thermoelectric, spintronic, and memory devices.

Atomic-scale study of the amorphous-to-crystalline phase transition mechanism in GeTe thin films.

The underlying mechanism driving the structural amorphous-to-crystalline transition in Group VI chalcogenides is still a matter of debate even in the simplest GeTe system. We exploit the extreme sensitivity of Fe emission Mössbauer spectroscopy, following dilute implantation of Mn (T½ = 1.5 min) at ISOLDE/CERN, to study the electronic charge distribution in the immediate vicinity of the Fe probe substituting Ge (Fe), and to interrogate the local environment of Fe over the amorphous-crystalline phase transition in GeTe thin films.

Solid-state dewetting of ultra-thin Au films on SiO₂ and HfO₂.

Ultra-thin Au films with thickness (h) ranging from 0.5 to 6.0 nm were deposited at room temperature (RT) by means of e-beam evaporation on SiO2 and HfO2.

Phase stabilization of Al:HfO2 grown on In(x)Ga(1-x)As substrates (x = 0, 0.15, 0.53) via trimethylaluminum-based atomic layer deposition.

Al:HfO2 is grown on III-V compound substrates by atomic layer deposition after an in situ trimethylaluminum-based preconditioning treatment of the III-V surface. After post-deposition rapid thermal annealing at 700 °C, the cubic/tetragonal crystalline phase is stabilized and the chemical composition of the stack is preserved. The observed structural evolution of Al:HfO2 on preconditioned III-V substrates shows that the in-diffusion of semiconductor species from the substrate through the oxide is inhibited.

Metal organic chemical vapor deposition of phase change Ge1Sb2Te4 nanowires.

The self-assembly of Ge(1)Sb(2)Te(4) nanowires (NWs) for phase change memories application was achieved by metal organic chemical vapor deposition, catalyzed by Au nanoislands in a narrow range of temperatures and deposition pressures. In the optimized conditions of 400 °C, 50 mbar, the NWs are Ge(1)Sb(2)Te(4) single hexagonal crystals. Phase change memory switching was reversibly induced by nanosecond current pulses through metal-contacted NWs with threshold voltage of about 1.

Si nanocrystal synthesis in HfO2/SiO/HfO2 multilayer structures.

The synthesis of two-dimensional arrays of Si nanocrystals in an HfO2 matrix has been achieved by deposition of HfO2/SiO/HfO2 multilayer structures followed by high temperature (1100 degrees C) thermal treatment in nitrogen atmosphere. Silicon out-diffusion from the SiO layer through the HfO2 films has been shown to be the limiting factor in the formation of the Si nanocrystals. Suitable strategies have been identified in order to overcome this limitation.

[Local effects and changes in wound drainage in the free peritoneal cavity].

In a prospective randomised study 30 mongrel rabbits received two standard colon-resections. Three types of drains were tested: (latex-rubber-) Penrose-drains, rubbertube- and silicontube-drains, which were placed in the lower abdomen. As a closed drainage-system the extraperitoneal tip of the drain was placed in a closed subcutis-pocket.

[Can the diffractive multifocal posterior chamber lens be implanted in routine lens implantation?].

Three different types of diffractive IOLs were implanted in the eyes of 140 patients who were followed up for 2 years. The latest follow-up included: near and distance visual acuity, glare and low-contrast visual acuity. We ask the patients when they wear glasses.

[Clinical results after implantation of a multifocal diffractive posterior chamber lens].

45 diffractive multifocal posterior chamber lenses were implanted in 41 patients. The follow-up time amounted to 12 months. With one correction good visual acuity for far and as well as near distances could be achieved.

[Implantation of folding posterior chamber lenses].

The implantation of foldable intraocular lenses (IOL) takes advantages of the benefit of small incision cataract surgery provided by phacoemulsification. However, even experienced surgeons may find the new implantation techniques required initially difficult. Advantages of small incision techniques include maintaining stability of the globe during surgery, especially in the case of acute IOP elevation caused by choroidal effusion or expulsive hemorrhage, as well as improved postoperative healing.

[Tonography and fluorophotometry in the clinical study of aqueous humor dynamics].

We used Grant's tonography and fluorophotometry (the Jones and Maurice method) to study the aqueous humor dynamics in normal and glaucomatous eyes. The results of the two methods were compared. The mean facility and rate of aqueous flow in normal eyes were similar.

Influence of imipenem on the serum resistance of enterobacteriaceae.

Following growth in a subinhibitory concentration of imipenem and additional incubation in a 20% dilution of normal human serum (NHS) for 90 minutes, five of 12 serum-resistant strains of enterobacteriaceae showed a decrease in colony-forming units of two or more logs of growth compared with the control. Two strains (of Escherichia coli and Enterobacter aerogenes) showed this phenomenon even with incubation in 5% NHS. Treatment with imipenem did not change the serum resistance of the other seven strains (two strains each of Enterobacter cloacae, Klebsiella pneumonia, and Serratia marcescens, and one strain of Proteus morganii).