Growth process, characterization, and modeling of electronic properties of coupled InAsSbP nanostructures

Quaternary III-V InAsSbP quantum dots (QDs) have been grown in the form of cooperative InAsSb/InAsP structures using a modified version of the liquid phase epitaxy. High resolution scanning electron microscopy, atomic force microscopy, and Fourier-transform infrared spectrometry were used to investigate these so-called nano-camomiles, mainly consisting of a central InAsSb QD surrounded by six InAsP-QDs, that shall be referred to as leaves in the following. The observed QDs average density ranges from 0.8 to 2 x 10(9) cm(-2), with heights and widths dimensions from 2 to 20 nm and 5 to 45 nm, respectively. The average density of the leaves is equal to (6-10) x 10(9) cm(-2) with dimensions of approx. 5 to 40 nm in width and depth. To achieve a first basic understanding of the electronic properties, we have modeled these novel nanostructures using second-order continuum elasticity theory and an eight-band k . p model to calculate the electronic structure. Our calculations found a clear localization of hole states in the central InAsSb dot. The localization of electron states, however, was found to be weak and might thus be easily influenced by external electric fields or strain. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3624621

Room temperature magnetoelectric properties of type-II InAsSbP quantum dots and nanorings

Quaternary InAsSbP quantum dots (QDs) and quantum rings (QRs) are grown on InAs (100) substrates by liquid phase epitaxy. High resolution scanning electron and atomic force microscopes are used for the characterization. The room temperature optoelectronic and magnetoelectric properties of the InAsSbP type-II QDs and QRs are investigated. For the QD-based structures, specific dips on the capacitance-voltage characteristic are revealed and measured, which are qualitatively explained by the holes thermal and tunnel emissions from the QDs. Specific fractures at room temperature are experimentally found in the magnetic field dependence of an electric sheet resistance for the InAsSbP QRs-based sample. (C) 2012 American Institute of Physics. (doi:10.1063/1.3676437

Preparation of SnO2 Films with Thermally Stable Nanoparticles

Different regimes of preparations of nano-sized particles of SnO2 are considered. The films technology ensuring weak dependence of grains size on films calcinations temperature is offered

Preparation of SnO2 Films with Thermally Stable Nanoparticles

Abstract: Different regimes of preparations of nano-sized particles of SnO2 are considered. The films technology ensuring weak dependence of grains size on films calcinations temperature is offered

Noise Spectroscopy of Gas Sensors

We study current-voltages and low-frequency noise characteristics of the metal—porous silicon—silicon single crystal—metal structure with 50% and 73% porosity of porous silicon. The study is performed in dry air and in a mix of dry air with carbon monoxide of different concentrations. The Hooge noise parameter and the parameter in the frequency dependence of the noise voltage spectral density S(f) were determined from experimental data. High sensitivity of spectral dependence of noise to gas concentration allows offering powerful method for determination of gas concentration in the air or environment

The ethanol sensors made from alpha-Fe2O3 decorated with multiwall carbon nanotubes

Thin film ethanol sensors made from alpha-Fe2O3 decorated with multiwall carbon nanotubes (MWCNTs) were manufactured by the electron beam deposition method. The morphology of the decorated alpha-Fe2O3/MWCNTs (25:1 weight ratios) nanocomposite powder was investigated using the scanning electron microscopy and X-ray diffraction techniques. The thickness of thin films has been determined from ellipsometric measurements. The response of manufactured sensors was investigated at different temperatures of the sensor work body and concentration of gas vapors. Good response of prepared sensors to ethanol vapors already at work body temperature of 150 degrees C was shown