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A multiquantum well (MQW) double-drift region (DDR) impact avalanche transit time (IMPATT) device based on Si/3C-SiC material system has been proposed for high frequency application. One symmetrical and two asymmetrical doping profiles for the proposed hetero-structure device are considered in the present study. The design and optimization of the abovementioned three doping profiles of SÌ/3C-SÌC MQW...
The spectrometric characteristics of semi-insulating GaAs detectors irradiated by 5 MeV electrons to a dose of 24 kGy at three different dose rates (20, 40 and 80kGy/h) were studied. A similar decrease of CCE (Charge Collection Efficiency) after irradiation by 7.5% of CCE was observed with all groups of investigated detectors. On the other hand, an increase of detection efficiency after irradiation...
The resistivity, Hall coefficient, Hall mobility, and Hall concentration in undoped semi-insulating GaAs samples irradiated by 5 MeV electrons of various cumulative doses ranging from 1kGy to 24 kGy and different dose rate were measured and analysed at the temperature 400 K and 300 K. The resistivity and the electron Hall concentration decrease while Hall coefficient and the electron Hall mobility...
In this work an ARC based GaAs solar cell having both homojunction and heterojunction has been simulated. The cell structure consist of TCO/a-Si:H(p)/GaAs(p)/GaAs(n)/a-Si:H(n)/TCO. The structure has been simulated using Silvaco TCAD. This structure gives higher fill factor due to the reduced series resistance and hence results better efficiency. The work function of the transparent conductive oxide...
We report on the operation of electrically pumped 1.3µm InAs QD laser directly grown on a Si substrate using InAlAs/GaAs dislocation filter layers with a threshold current density of 194A/cm2 and output power of ~80mW.
Flexible electronics using gallium arsenide (GaAs) for nano-electronics with high electron mobility and optoelectronics with direct band gap are attractive for many applications. Here we describe a state-of-the-art CMOS compatible batch fabrication process of transforming traditional electronic circuitry into large-area flexible, semi-transparent platform. We show a simple release process for peeling...
The photo-thermal properties of vertically etched gallium arsenide nanowire arrays are examined using Raman spectroscopy. The nanowires are arranged in square lattices with a constant pitch of 400 nm, and diameters ranging from 50 to 155 nm. The arrays were illuminated using a 532 nm laser with an incident energy density of 10 W/mm2. Nanowire temperatures were highly dependent on the nanowire diameter,...
We describe recent developments on 1.3 μm InAs/GaAs quantum dot lasers epitaxially grown on silicon by molecular beam epitaxy. Record high output powers, lasing temperatures, and operating lifetimes among GaAs based lasers epitaxially grown on silicon have been achieved.
We demonstrate the growth of III-Sb buffers on GaAs and Silicon substrates through the use of an epitaxial technique involving the formation of interfacial misfit dislocation arrays that is formed between the III-Sb alloy and the substrate. The interfacial misfit array results in the spontaneous relaxation of the highly mismatched III-Sb semiconductor and provides a platform for the realization of...
Over the last 25 years has seen an unprecedented increase in the growth of phonic components based on semiconductor and solid-state lasers, glass and polymer based optical fibres, and organic LEDs. Emerging technology for component engineering must embed dissimilar materials based devices into an integrated form which is more efficient. In this article, we demonstrate techniques for overcoming the...
A possibility to combine the meta-GGA exchange functional suggested by Tran and Blaha with the LDA pseudopotentials was investigated and a simple extension allowing for the direct reduction of the band gap error was suggested. A set of 19 semiconducting materials was used for testing. The mean absolute value of the relative band gap error was found to be 2.5 times larger than in the case when meta-GGA...
Effects of annealing on GaAs/Si bonding interfaces of III-V-on-Si hybrid tandem solar cells were investigated. Using a cross sectional transmission electron microscope, an amorphous layer was observed at the interfaces of GaAs/Si junctions that had been fabricated by the surface active bonding method. The amorphous layer vanished after the annealing at 400 °C. We also investigated the effects of the...
This paper deals with comparisons of noise spectroscopy and I-V characteristic of semiconductor lasers diodes GaAs with InAs quantum dots layer. We studied two groups with different technologies (A and B). Each group had 4 samples. The samples were quality screened using noise analysis. From the measurement results it follows that the noise spectral density related to defects is of 1/f or and can...
32 Gbaud QPSK and 16QAM field trial transmission over 560 km Telecom Italia's metro domestic network, in a realistic multi-vendor environment with legacy channels, has been performed using the first SOI-compatible GaAs IQ-modulator developed within the EU project GALACTICO.
Ferroelectric epitaxial Pb(Zr, Ti)O3(PZT) layers were grown by pulsed laser deposition on SrTiO3/GaAs templates fabricated by molecular beam epitaxy. The templates present an excellent structural quality and the SrTiO3/GaAs is abrupt at the atomic scale. The PZT layers contain a- and c- domains, as shown by X-Ray diffraction analyses. Piezoresponse force microscopy experiments and macroscopic electrical...
The nature of the ground optical transition in (In, Ga)As/GaP quantum dots is thoroughly investigated through k·p calculations and a supercell tight-binding simulation. Quantum dot morphology is deduced from scanning-tunneling-microscopy images. The strain field has a strong influence on the conduction band states. Indeed, for a pure GaAs QD, the wavefunction of the ground electron state is spatially...
Power amplifiers (PAs) are used in the wide range of electronics such as RADAR, base stations, jammers and cable TV applications. These amplifiers can achieve design specifications like high efficiency and high output power (>20W) as much as the capability of the transistor. For this reason; Si LDMOSFETs, GaN HEMTs and GaAs HFETs are advancing their place in the market. In this article; GaN, Si,...
The paper considers a model of misfit dislocation determination to establish the dislocation free contour map for nanotemplate geometrical size. Dislocation free contour map has been obtained for GaN and GaAs nanostructures on the substrate of AlN and Si, respectively. The results of Burger dislocation determination in nanostructures are proved by experiment and show good agreement.
The in-depth photon counting x-ray detector (PCXD) is a multi-layer detector arrangement which has been introduced to tackle photon count rate limitations of current systems. The capability of resolving photon detections along the detector's depth direction enables multiple measurements in a single scan with energy information that could be potentially utilized for x-ray spectral imaging. The benefit...
Continuous down scaling of MOSFET has resulted in increased short channel and tunneling leakages implying the need for alternate devices such as TFET. The tunneling current is controlled by gate voltage by varying the width of band-to-band tunneling barrier. In this paper, analytical study of a vertical double gate TFET is presented. The tunneling probability and current are derived and analyzed to...
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