Improved CdZnTe detectors grown by vertical Bridgman process

1997 ◽  
Vol 484 ◽  
Author(s):  
K. G. Lynn ◽  
M. Weber ◽  
H. L. Glass ◽  
J. P. Flint ◽  
Cs. Szeles
Keyword(s):  
Room Temperature ◽  
High Resistivity ◽  
Detector Response ◽  
Processing Conditions ◽  
Bridgman Technique ◽  
X Ray ◽  
Zn Content ◽  
Vertical Bridgman ◽  
Γ Ray ◽  
Cdznte Detectors

AbstractThe γ ray (57Co) and a particle (241Am) detector response of Cd1−xZnxTe crystals grown by vertical Bridgman technique was studied under both positive and negative bias conditions. Postgrowth processing was utilized to produce a high-resistivity material with improved chargecollection properties. Samples of various Zn concentrations were investigated by I–V measurements and thermally stimulated spectroscopies to determine the ionization energies of deep levels in the band gap. When the post-processing conditions were optimized the lowenergy tailing of the γ-ray photopeaks was significantly reduced and an energy resolution of under 5% was achieved for the 122 keV γ-photon line in crystals with x=0.2 Zn content at room temperature. A peak to background ratio of 14:1 for the 122 keV photopeak from 57Co was observed on the best sample, using a standard planar detection geometry. The low-energy 14.4 keV X-ray line could also be observed and distinguished from the noise.

Improved CdZnTe detectors grown by vertical Bridgman Process

1997 ◽  
Vol 487 ◽  
Author(s):  
K. G. Lynn ◽  
M. Weber ◽  
H. L. Glass ◽  
J. P. Flint ◽  
Cs. Szeles
Keyword(s):  
Room Temperature ◽  
High Resistivity ◽  
Detector Response ◽  
Processing Conditions ◽  
Bridgman Technique ◽  
X Ray ◽  
Zn Content ◽  
Vertical Bridgman ◽  
Γ Ray ◽  
Cdznte Detectors

AbstractThe γ ray (57Co) and α particle (241Am) detector response of Cdl-xZnxTe crystals grown by vertical Bridgman technique was studied under both positive and negative bias conditions. Postgrowth processing was utilized to produce a high-resistivity material with improved chargecollection properties. Samples of various Zn concentrations were investigated by I-V measurements and thermally stimulated spectroscopies to determine the ionization energies of deep levels in the band gap. When the post-processing conditions were optimized the lowenergy tailing of the γ-ray photopeaks was significantly reduced and an energy resolution of under 5% was achieved for the 122 keV γ-photon line in crystals with x=0.2 Zn content at room temperature. A peak to background ratio of 14:1 for the 122 keV photopeak from 57Co was observed on the best sample, using a standard planar detection geometry. The low-energy 14.4 keV X-ray line could also be observed and distinguished from the noise.

scholarly journals Characteristics of X-ray and gamma radiation detectors based on polycrystalline CdTe and CdZnTe films

2021 ◽  
pp. 81-86
Author(s):  
Sharifa Utamuradova ◽  
Sultanposha Muzafarova ◽  
Abdulla Abdugafurov ◽  
Kakhramon Fayzullaev ◽  
Elmira Naurzalieva ◽  
...  
Keyword(s):  
Room Temperature ◽  
Specific Resistance ◽  
Radiation Detectors ◽  
Columnar Structure ◽  
Nuclear Materials ◽  
X Ray ◽  
Molybdenum Substrate ◽  
Cdznte Detectors ◽  
And Control ◽  
Polycrystalline Semiconductor

Based on CdTe and CdZnTe detectors a number of promising devices were created, which found their application in metallurgy, in solving the problems of customs control and control of nuclear materials, as well as matrix detectors created for the manufacture of medical devices and devices for space research. Detectors, created on the basis of polycrystalline semiconductor CdTe and CdZnTe films with a columnar structure on a molybdenum substrate with a thickness d = 30150 μm, had a specific resistance p > 10^5 10^8 W-cm. The energy resolution of the CdTe and CdZnTe detectors at room temperature reached ~ 5 keV on the 59.6 keV 241Am line.

Room-temperature X-ray response of cadmium–zinc–telluride pixel detectors grown by the vertical Bridgman technique

2020 ◽  
Vol 27 (2) ◽  
pp. 319-328 ◽  
Author(s):  
Leonardo Abbene ◽  
Fabio Principato ◽  
Gaetano Gerardi ◽  
Antonino Buttacavoli ◽  
Donato Cascio ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cadmium Zinc Telluride ◽  
Photon Counting ◽  
Zinc Telluride ◽  
High Rate ◽  
High Flux ◽  
X Ray ◽  
Pixel Detectors ◽  
Vertical Bridgman ◽  
Cadmium Zinc

In this work, the spectroscopic performances of new cadmium–zinc–telluride (CZT) pixel detectors recently developed at IMEM-CNR of Parma (Italy) are presented. Sub-millimetre arrays with pixel pitch less than 500 µm, based on boron oxide encapsulated vertical Bridgman grown CZT crystals, were fabricated. Excellent room-temperature performance characterizes the detectors even at high-bias-voltage operation (9000 V cm−1), with energy resolutions (FWHM) of 4% (0.9 keV), 1.7% (1 keV) and 1.3% (1.6 keV) at 22.1, 59.5 and 122.1 keV, respectively. Charge-sharing investigations were performed with both uncollimated and collimated synchrotron X-ray beams with particular attention to the mitigation of the charge losses at the inter-pixel gap region. High-rate measurements demonstrated the absence of high-flux radiation-induced polarization phenomena up to 2 × 106 photons mm−2 s−1. These activities are in the framework of an international collaboration on the development of energy-resolved photon-counting systems for high-flux energy-resolved X-ray imaging.

Monte Carlo Calculation of X-Rays Deposited Energy in CdZnTe Detector

2007 ◽  
Vol 555 ◽  
pp. 141-146 ◽  
Author(s):  
Srboljub J. Stanković ◽  
M. Petrović ◽  
M. Kovačević ◽  
A. Vasić ◽  
P. Osmokrović ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Calculation ◽  
Absorbed Dose ◽  
Detector Response ◽  
X Rays ◽  
X Ray ◽  
Cdznte Detector ◽  
Deposited Energy ◽  
Photon Direction ◽  
Cdznte Detectors

CdZnTe detectors have been employed in diagnostic X-ray spectroscopy. This paper presents the Monte Carlo calculation of X-ray deposited energy in a CdZnTe detector for different energies of photon beam. In incident photon direction, the distribution of absorbed dose as deposited energy in detector is determined. Based on the dependence of the detector response on the thickness and different Zn fractions, some conclusions about changes of the material characteristics could be drawn. Results of numerical simulation suggest that the CdZnTe detector could be suitable for X-ray low energy.

Effects of Vacancies on the Thermal Expansion of Mercury Indium Telluride Crystals

2010 ◽  
Vol 663-665 ◽  
pp. 1008-1011
Author(s):  
Ling Hang Wang
Keyword(s):  
Thermal Expansion ◽  
Room Temperature ◽  
Linear Expansion ◽  
Semiconductor Material ◽  
X Ray ◽  
Temperature Range ◽  
Vertical Bridgman ◽  
Indium Telluride

The thermal expansion of a novel semiconductor material, mercury indium telluride (MIT) grown by vertical Bridgman (VB) method, was measured from room temperature till 573K by two methods, i.e. Macroscopic dilatometric and X-ray measurements. It is found that the macroscopic expansion is quite different from the expansion of the lattice (micro-expansion). The macroscopic expansion is lower than micro-expansion in the temperature range of 303-425.5K and has a minimum of -0.14% linear expansion, while the macro-expansion becomes larger than micro-expansion in the temperature higher than 425.5K. The former may be due to the effects of the existing neutral vacancies. The latter may result from the influence of thermal-activated vacancies on the lattice.

Crystal growth of CuInSe2 by the Bridgman method

1989 ◽  
Vol 67 (4) ◽  
pp. 294-297 ◽  
Author(s):  
W. S. Weng ◽  
L. S. Yip ◽  
I. Shih ◽  
C. H. Champness
Keyword(s):  
Crystal Growth ◽  
Room Temperature ◽  
Amorphous Layer ◽  
Bridgman Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertical Bridgman ◽  
Hall Effect Measurements ◽  
Rotation Technique ◽  
Crucible Rotation

Single crystals of CuInSe2 have been fabricated by the vertical Bridgman method. A conventional Czochralski crystal-pulling system was adapted for this purpose. An accelerated crucible-rotation technique was employed for a better mixing of the melt during the growth. Void- and crack-free crystal grains with an area as large as 50 mm2 and a thickness of more than 5 mm could be selectively cut from the ingots. From room-temperature Hall-effect measurements, mobility values as large as 73 cm2 ∙ V−1 ∙ s−1 were obtained for the present samples. X-ray diffraction studies suggested that abrasive polishing might create an amorphous layer on the surface of the CuInSe2 crystals.

Growth and Initial Characterization of Novel Hgte-Based II-VI Materials

1989 ◽  
Vol 161 ◽  
Author(s):  
F.G. Moore ◽  
J.C. Abele ◽  
R.E. Kremer
Keyword(s):  
Room Temperature ◽  
Energy Gap ◽  
Segregation Coefficient ◽  
Bridgman Technique ◽  
Density Measurements ◽  
Mobility Data ◽  
Initial Characterization ◽  
Vertical Bridgman ◽  
Effective Segregation Coefficient

ABSTRACTHg1−xAxTe materials where A= {Be, Mg, Ba, Sr, Ca} have been synthesized by the vertical Bridgman technique. Hydrostatic density measurements showing segregation are presented and for HgMgTe an effective segregation coefficient is obtained. For HgMgTe a relationship between bandgap E and composition x, is developed based on FTIR measurements of cut-on wavelengths. The variation of energy gap with composition is found to be comparable to that of HgMnTe and twice as rapid as that of HgCdTe. Carrier concentration and mobility data from room temperature and 77K Hall measurements are presented for samples annealed in a saturated overpressure of Mercury.

In situ growth of an ethyl p-hydroxybenzoate single crystal by the vertical Bridgman technique: a potential nonlinear optical material for third-harmonic generation

2021 ◽  
Vol 54 (5) ◽  
pp. 1340-1348
Author(s):  
Debabrata Nayak ◽  
N. Vijayan ◽  
Manju Kumari ◽  
Kiran ◽  
Nikita Vashistha ◽  
...  
Keyword(s):  
Single Crystal ◽  
Laser Damage Threshold ◽  
Laser Source ◽  
Dihydrogen Phosphate ◽  
X Ray Diffraction ◽  
Bridgman Technique ◽  
Third Order ◽  
X Ray ◽  
The Third ◽  
Vertical Bridgman

Optically transparent single crystals of ethyl p-hydroxybenzoate (EPHB) were successfully grown by the vertical Bridgman technique. The crystalline phase and unit-cell dimensions were obtained from powder X-ray diffraction using Rietveld analysis. The presence of defects and grain boundaries was investigated by high-resolution X-ray diffraction. The optical quality of the grown single crystal was assessed by UV–Vis and photoluminescent spectroscopies. A blue emission, with a bi-exponential decay time, was obtained from time-resolved photoluminescence upon laser excitation at 266 nm. The mechanical strength of the EPHB single crystal was studied by Vickers hardness testing. A decrease in the laser-damage threshold was observed with a nanosecond Nd:YAG laser source for increased pulse repetition rates. The third-order nonlinearity, nonlinear absorption coefficient and nonlinear refractive index were measured using the Z-scan technique with a femtosecond Ti:sapphire laser. The third-order nonlinear coefficient values for the grown crystal were compared with those of a potassium dihydrogen phosphate single crystal.

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