A5018530031- Advanced Semiconductor Detectors and Materials
- Semiconductor Quantum Structures and Devices
- Radiation Detection and Scintillator Technologies
- Chalcogenide Semiconductor Thin Films
- Advanced X-ray and CT Imaging
- Glass properties and applications
- Graphene research and applications
- Luminescence Properties of Advanced Materials
- Phase-change materials and chalcogenides
- Silicon Carbide Semiconductor Technologies
- Semiconductor materials and interfaces
- Nuclear Materials and Properties
- Laser-induced spectroscopy and plasma
- Planetary Science and Exploration
- Photonic and Optical Devices
- Magneto-Optical Properties and Applications
- Quantum Dots Synthesis And Properties
- Particle Detector Development and Performance
- Astro and Planetary Science
- Spectroscopy and Laser Applications
- Perovskite Materials and Applications
- Optical and Acousto-Optic Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Solid-state spectroscopy and crystallography
- Plasmonic and Surface Plasmon Research
Charles University
2015-2024
Czech Academy of Sciences, Institute of Physics
2015-2024
Czech Academy of Sciences, Institute of Physics of Materials
2017
Central European Institute of Technology
2017
Mansoura University
2017
Brookhaven National Laboratory
2016
Savannah River National Laboratory
2016
University of Surrey
2016
Redlen Technologies (Canada)
2016
Pennsylvania State University
2016
Abstract X- and gamma-ray detectors have broad applications ranging from medical imaging to security, non-proliferation, high-energy physics astrophysics. Detectors with high energy resolution, e.g. less than 1.5% resolution at 662 keV room temperature, are critically important in most uses. The efficacy of adding selenium the cadmium zinc telluride (CdZnTe) matrix for radiation detector has been studied. In this paper, growth a new quaternary compound Cd 0.9 Zn 0.1 Te 0.98 Se 0.02 by...
Because of its ideal band gap, high density and electron mobility-lifetime product, cadmium zinc telluride (CdZnTe or CZT) is currently the best room-temperature compound-semiconductor X- gamma-ray detector material. However, because innate poor thermo-physical properties above unity segregation coefficient for Zn, wide spread deployment this material in large-volume CZT detectors still limited by production cost. The underlying reason low yield high-quality that suffers from three major...
The phase-transition of atomically thin graphene coating into a diamond phase increases the hardness and fracture toughness SiC even for indentation depths 10 μm compared to bare SiC, which is against general indirect relation.
We investigated the feasibility of long-drift-time CdZnTe (CZT) gamma-ray detectors, fabricated from CZT material produced by Redlen Technologies. crystals with cross-section areas 5 × mm2 and 6 thicknesses 20-, 30-, 40-, 50-mm were configured as 3D position-sensitive drift detectors read out using a front-end ASIC. By correcting electron charge losses caused defects in crystals, we demonstrated high performance for relatively thick unselected material.
Space weathering is a process that changes the surface of airless planetary bodies. Prime space agents are solar wind irradiation and micrometeoroid bombardment. These processes alter reflectance spectra often modify their compositional diagnostic features. In this work we focused on simulating comparing spectral caused by bombardment to gain better understanding these individual processes. We used olivine pyroxene pellets as proxies for materials. To simulate hydrogen, helium, argon ions...
Abstract Single crystals of lead-free halide double perovskite Cs 2 AgBiBr 6 sensor material manifest a remarkable potential for application in radiation detection and imaging. In this study, the purity crystallinity solution-grown single with cubic Fm $$\overline{3}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mn>3</mml:mn> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> m symmetry have been corroborated by powder XRD measurements, while crystal patterns reveal...
In recent years, graphene growth optimization has been one of the key routes towards large-scale, high-quality production. We have measured in-situ residual gas content during epitaxial on silicon carbide (SiC) to find detrimental factors growth. The conditions in high vacuum and purified argon are compared. grown is studied by Raman scattering mapping mechanical strain, charge density, number layers grain size evaluated. Charge density carrier mobility Hall effect measurements van der Pauw...
A study of deep levels in CdZnTeSe radiation-detection materials is presented. The approach relies on electrical methods that combine time and temperature evolution the electric field current after switching bias voltage. Two optical were also applied to levels. first method utilizes temporal analysis off an additional light illuminating sample at a wavelength 940 nm. second involved measuring spectral dependence during near infrared illumination. results are compared with those obtained...
Abstract A systematic study of the doping ability TeO 2 –ZnO–BaO glassy system with Er 3+ ions is presented to achieve strong Stokes/upconversion photoluminescence (UPL) emission and determine optimal experimental conditions for conducting Judd–Ofelt (JO) analysis in Er-doped materials using newly introduced Combinatorial JO this work. Selected samples across glass-forming region following concentration trends each constituent oxide were uniformly doped 0.2 mol. <mml:math...
A method is presented for the determination of carrier drift mobility, lifetime, electric field distribution, and dynamics space charge formation, including detrapping energy capture cross-section dominant trap level in polarizing semiconductor radiation detectors. The procedure stems from laser-induced transient current measurements done at a steady-state pulsed biasing variable temperature. approach allows us direct detector parameters measured data without complex mathematical treatment....
In this contribution we demonstrate both experimentally and theoretically the possibility to control profile of internal electric field by compensation space charge formed carriers trapped at deep levels QT with present due band bending metal/CdTe interface QM. The demonstrated mechanism represents a promising way decrease problems associated collection efficiency in CdTe x-ray detectors operated high fluxes photons.
In this contribution we introduce a method of deep level spectroscopy in semi-insulating semiconductors demonstrated on detector-grade bulk CdZnTe. The is based the measurements temporal and temperature evolution electric field profile studied samples, which very sensitive to change occupancy levels. measurement linear electro-optic (Pockels) effect using InGaAs avalanche photodiode with fast response. internal samples significantly changes under various external conditions represented by...
The traditional method for electron lifetime measurements of CdZnTe (CZT) detectors relies on using the Hecht equation. procedure involves measuring dependence detector response applied bias to evaluate μτ product, which in turn can be converted into carrier lifetime. Despite general acceptance this technique, is very convenient comparative testing different CZT materials, assumption a constant electric field inside unjustified. In equation, means that drift time would linear function...
This work is focused on a detailed study of pulsed mode infrared light induced depolarization CdZnTe detectors operating at high photon fluxes. depolarizing effect result the decrease positive space charge that caused by trapping photogenerated holes deep level. The reduction in due to optical transition electrons from valence band level additional illumination. In this paper, we present results pulse depolarization, which it possible keep detector depolarized state during its operation....
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation J. Franc, V. Dědič, M. Rejhon, Zázvorka, P. Praus, Touš, Sellin; Control of electric field in CdZnTe radiation detectors by above-bandgap light. Journal Applied Physics 28 April 2015; 117 (16): 165702. https://doi.org/10.1063/1.4919073 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends...
We investigated the influence of deep levels on electrical transport properties CdZnTeSe radiation detectors by comparing experimental data with numerical simulations based simultaneous solution drift-diffusion and Posisson equations, including Shockley-Read-Hall model carrier trapping. determined Schottky barrier height Fermi level position from I-V measurements. measured time evolution electric field current after application a voltage bias. observed that CZTS are fundamentally governed...
We present a study of the polarization phenomena in n-type cadmium zinc telluride material with gold contacts that showed upwards bending bands near metal–semiconductor (M–S) interface. The dynamic electric field distribution along sample due to accumulation positive space charge below cathode at M–S interface was studied by means Pockels effect. analysis time, bias and temperature variation values has provided parameters deep donor responsible for mechanisms CdZnTe.
We studied polarization in semi-insulating detector-grade cadmium zinc telluride without and with high optical flux. employed the Pockels electro-optic effect combined two perpendicular sources of light. A beam red light or an infrared laser was applied parallel to direction electric field acting as a source electron–hole pairs. Infrared radiation from monochromator illuminated sample changed occupation deep levels therefore depth profile bulk field. Spectral measurements were used determine...
This paper describes an application of infrared light-induced de-polarization applied on a polarized CdZnTe detector working under high radiation fluxes. We newly demonstrate the influence flux X-rays and simultaneous 1200-nm LED illumination spectroscopic properties detector. detectors operating fluxes usually suffer from polarization effect, which occurs due to screening internal electric field by positive space charge caused photogenerated holes trapped at deep level. Polarization results...
We report our simulations on the influence of contacts charge collection in semi-insulating (CdZn)Te with Au under radiation flux, employing simultaneous solutions drift-diffusion and Poisson equations. The type space distribution electric field Au/(CdZn)Te/Au structure at high fluxes reflect combined generated by band bending electrodes, from photogenerated carriers trapped deep levels. show that originating latter approaches dominance while becomes negligible. ratio trapping times low...
One of the main complications for interpretation reflectance spectra airless planetary bodies is surface alteration by space weathering caused irradiation solar wind and micrometeoroid particles. We aim to evaluate damage samples from H laser relate it observed in spectra. used olivine (OL) pyroxene (OPX) pellets irradiated 5 keV ions individual fs pulses measured their visible (VIS) near-infrared (NIR) with scanning transmission electron microscopy. studied structural, mineralogical,...