Alkali Metal Chalcogenides for Radiation Detection

2011 ◽  
Vol 1341 ◽  
Author(s):  
J. A. Peters ◽  
Zhifu Liu ◽  
B. W. Wessels ◽  
I. Androulakis ◽  
C. P. Sebastian ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Alkali Metal ◽  
Charge Transport ◽  
Band Gap ◽  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detector ◽  
Radiation Detection ◽  
Charge Carriers ◽  
Metal Chalcogenides

ABSTRACTWe report on the optical and charge transport properties of novel alkali metal chalcogenides, Cs2Hg6S7 and Cs2Cd3Te4, pertaining to their use in radiation detection. Optical absorption, photoconductivity, and gamma ray response measurements for undoped crystals were measured. The band gap energies of the Cs2Hg6S7 and Cs2Cd3Te4 compounds are 1.63 eV and 2.45 eV, respectively. The mobility-lifetime products for charge carriers are of the order of ~10-3 cm2/V for electrons and ~10-4 cm2/V for holes. Detectors fabricated from the ternary compound Cs2Hg6S7 shows well-resolved spectroscopic features at room temperature in response to ϒ -rays at 122 keV from a 57Co source, indicating its potential as a radiation detector.

scholarly journals Quaternary Semiconductor Cd1-xZnxTe1-ySey for High-Resolution, Room-Temperature Gamma-Ray Detection

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 827
Author(s):  
Sandeep K. Chaudhuri ◽  
Joshua W. Kleppinger ◽  
OmerFaruk Karadavut ◽  
Ritwik Nag ◽  
Krishna C. Mandal
Keyword(s):  
Crystal Growth ◽  
High Resolution ◽  
Charge Transport ◽  
Single Crystals ◽  
Homeland Security ◽  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detector ◽  
Growth Yield ◽  
Charge Trapping

The application of Cd0.9Zn0.1Te (CZT) single crystals, the primary choice for high-resolution, room-temperature compact gamma-ray detectors in the field of medical imaging and homeland security for the past three decades, is limited by the high cost of production and maintenance due to low detector grade crystal growth yield. The recent advent of its quaternary successor, Cd0.9Zn0.1Te1-ySey (CZTS), has exhibited remarkable crystal growth yield above 90% compared to that of ~33% for CZT. The inclusion of Se in appropriate stoichiometry in the CZT matrix is responsible for reducing the concentration of sub-grain boundary (SGB) networks which greatly enhances the compositional homogeneity and growth yield. SGB networks also host defect centers responsible for charge trapping, hence their reduced concentration ensures minimized charge trapping. Indeed, CZTS single crystals have shown remarkable improvement in electron charge transport properties and energy resolution over CZT detectors. However, our studies have found that the overall charge transport in CZTS is still limited by the hole trapping. In this article, we systematically review the advances in the CZTS growth techniques, its performance as room-temperature radiation detector, and the role of defects and their passivation studies needed to improve the performance of CZTS detectors further.

Purity analysis for room-temperature semiconductor radiation detection material, CsPbBr3, using ICP-MS

2020 ◽  
Vol 35 (11) ◽  
pp. 2672-2678
Author(s):  
Ulrich Makanda ◽  
Alexandre Voinot ◽  
Ramjee Kandel ◽  
Yu Wu ◽  
Matthew Leybourne ◽  
...  
Keyword(s):  
Room Temperature ◽  
Radiation Detector ◽  
Radiation Detection ◽  
Impurity Analysis ◽  
Icp Ms ◽  
Purity Analysis

An ICP-MS protocol has been adapted to the impurity analysis of potential radiation detector, CsPbBr3. The newly developed method was validated by conducting a series of spike-and-recovery experiments based on solution synthesized CsPbBr3.

scholarly journals Influence of Air Annealing and Gamma Ray Irradiation on the Optical Properties of Cl16FePc Thin Films

2012 ◽  
Vol 9 (4) ◽  
pp. 2439-2445 ◽  
Author(s):  
Raji Koshy ◽  
C. S. Menon
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Optical Absorption ◽  
Band Gap ◽  
Gamma Ray ◽  
Optical Transition ◽  
High Electron ◽  
Glass Substrates ◽  
Optical Dielectric Constant

Metal phthalocyanines are one of the most promising candidates to be used in the fabrication of such devices. Among various phthalocyanines, Iron Hexadecachloro Phthalocyanine (Cl16FePc) has received less attention. Basic characteristics of Cl16FePc are not reported in literature. Hexadecacholoro phthalocyanines have attracted interest as possible n-type organic semiconductor with high electron mobility and good stability characteristics. In the present work we investigate the optical band gap of the Cl16FePc thin films from the optical absorption spectrum as a function of air annealing temperatures and their suitability for the fabrication of molecular electronic devices. Some optical properties of the samples were studied as a function of γ-radiation doses also. Optical transition is found to be of direct type and optical band gaps are determined by analyzing the absorption spectrum. Vacuum sublimed thin films of Iron hexadecachloro phthalocyanine were prepared at room temperature onto glass substrates at a base pressure of 10-5Torr on precleaned glass substrates using Hind Hivac 12A4 coating plant. The optical energy band gap Eg were calculated. The mechanism of optical absorption follow the rule of direct transition. In the present paper we also report refractive index, real and imaginary parts of optical dielectric constant etc. from the reflectance measurements.

Growth, Structural Characterization, and Optical Band Gap Anomaly in Cu-III3-VI5 and Cu-III5-VI8 Ternary Compounds

2001 ◽  
Vol 668 ◽  
Author(s):  
S. M. Wasim ◽  
C. Rincón ◽  
G. Marín ◽  
R. Márquez ◽  
G. Sánchez Pérez ◽  
...  
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Energy Gap ◽  
Valence Band Maximum ◽  
Charge Carriers ◽  
Ternary Compounds ◽  
Donor Acceptor ◽  
Cubic Structure ◽  
Acceptor Defect

ABSTRACTA comparative study of the chemical composition, crystal structure, carrier concentration, mobility, and the energy gap at room temperature of the selenides and tellurides of normal Cu- III-VI2 and ordered defect Cu-III3-VI5and Cu-III5-VI8 compounds, grown by Bridgman techniques, is made. It is established that these compounds have a chalcopyrite-related structure with the exception of CuIn5Se8 and CuGa5Te8 that have hexagonal and cubic structure, respectively. Smaller volume of the unit cell and lower concentration of the charge carrier of the 1:3:5 and 1:5:8 phases, as compared to the 1:1:2, are attributed to the presence of the ordered vacancies. A new mechanism of the scattering of the charge carriers with the donor-acceptor defect pair (DADP) is suggested to explain the low value of mobility in these compounds. The anomaly observed in the band gap is explained in terms of the relative shift of the conduction band minimum and valence band maximum due to the donor-acceptor defect pairs and cation vacancies, respectively.

The Research and Design of a Room-Temperature Nuclear Radiation CdZnTe Detector

2014 ◽  
Vol 1030-1032 ◽  
pp. 1370-1374
Author(s):  
Min Shen ◽  
Zhi Ling Tang
Keyword(s):  
Ohmic Contact ◽  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detector ◽  
Pulse Signal ◽  
High Gain ◽  
Nuclear Radiation ◽  
Detector Performance ◽  
Nuclear Radiation Detector ◽  
Research And Design

Cadmium zinc telluride (CZT) material is one of the preferred materials for the fabrication of X-ray and gamma-ray detector. In this paper, it is presented a room-temperature nuclear radiation detector system based on CZT material with planar electrode and ohmic-contact. The experimental validation and analysis of the designed system is carried out. At the same time, some research and design on the surface signal-readout method、the charge sensitive preamplifier circuit、pulse signal processing circuit and soft processing program is made. The signal from the CZT material exposed to the radiation through the experiment is successfully required. The signal from the experiment is correspondingly processed and validated. The potential factors that influence the detector performance are discussed. The conductive adhesive is the joint of the ohmic-contact electrode and the preamplifier circuitry. The preamplifier circuitry has high gain, rise time in the nanosecond level and little equivalent charge-noise. The research and experimental design base for the development of subsequent gamma spectrometer.

Time-of-flight study of electrical charge mobilities in liquid-crystalline zinc octakis(β-octoxyethyl) porphyrin films

2000 ◽  
Vol 15 (11) ◽  
pp. 2494-2498 ◽  
Author(s):  
Yang Yuan ◽  
Brian A. Gregg ◽  
Marcus F. Lawrence
Keyword(s):  
Charge Transport ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Thick Films ◽  
Time Of Flight ◽  
Charge Carriers ◽  
Electrical Charge ◽  
Charged Carrier ◽  
Flight Measurements ◽  
Discotic Mesophase

Time-of-flight measurements performed on micron-thick films of liquid-crystalline zinc octakis(β-octoxyethyl) porphyrin indicated that charge carriers possess significantly high drift mobilities, attaining approximately 0.01 cm2 V−1s −1 and 0.008 cm2 V−1s −1 for holes and electrons, respectively, at room temperature. Upon heating the samples from 300 to 420 K, causing the porphyrin to go from the solid-crystalline to the discotic mesophase, the mobilities did not decrease drastically, and remained at values slightly larger than half those observed at room temperature. Charge transport in this material conformed to the Scher–Montroll model, which attributes a distribution of hopping times to the propagation of the initially formed charged carrier packet. Analysis of the “universal” plots prescribed by this model yielded a dispersion factor of 0.5 for both charge carriers.

scholarly journals Comparison between Silicon-Carbide and diamond for fast neutron detection at room temperature

2018 ◽  
Vol 170 ◽  
pp. 08006 ◽  
Author(s):  
O. Obraztsova ◽  
L. Ottaviani ◽  
A. Klix ◽  
T. Döring ◽  
O. Palais ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Carbide ◽  
High Temperature ◽  
Band Gap ◽  
Room Temperature ◽  
Radiation Detection ◽  
Neutron Detection ◽  
High Energy ◽  
High Energy Resolution ◽  
Fast Neutrons

Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron yield and reactor environment. Such detector must be able to operate at high temperature (up to 600° C) and high neutron flux levels. It is worth nothing that a detector for industrial environment applications must have fast and stable response over considerable long period of use as well as high energy resolution. Silicon Carbide is one of the most attractive materials for neutron detection. Thanks to its outstanding properties, such as high displacement threshold energy (20-35 eV), wide band gap energy (3.27 eV) and high thermal conductivity (4.9 W/cm·K), SiC can operate in harsh environment (high temperature, high pressure and high radiation level) without additional cooling system. Our previous analyses reveal that SiC detectors, under irradiation and at elevated temperature, respond to neutrons showing consistent counting rates as function of external reverse bias voltages and radiation intensity. The counting-rate of the thermal neutron-induced peak increases with the area of the detector, and appears to be linear with respect to the reactor power. Diamond is another semi-conductor considered as one of most promising materials for radiation detection. Diamond possesses several advantages in comparison to other semiconductors such as a wider band gap (5.5 eV), higher threshold displacement energy (40-50 eV) and thermal conductivity (22 W/cm·K), which leads to low leakage current values and make it more radiation resistant that its competitors. A comparison is proposed between these two semiconductors for the ability and efficiency to detect fast neutrons. For this purpose the deuterium-tritium neutron generator of Technical University of Dresden with 14 MeV neutron output of 1010 n·s-1 is used. In the present work, we interpret the first measurements and results with both 4H-SiC and chemical vapor deposition (CVD) diamond detectors irradiated with 14 MeV neutrons at room temperature.

Photoconductivity in some III–V alloys

1970 ◽  
Vol 48 (16) ◽  
pp. 1874-1878 ◽  
Author(s):  
A. E. Taylor ◽  
E. Fortin
Keyword(s):  
Electrical Conductivity ◽  
Optical Absorption ◽  
Band Gap ◽  
Low Temperatures ◽  
Room Temperature ◽  
Alloy Composition ◽  
Energy Gaps ◽  
Sensitivity Curves ◽  
Alloy Concentration ◽  
Absorption Measurements

Photoconducting properties of GaAs–InAs and GaAs–GaSb alloys were investigated at room and low temperatures. The peaks in the photoresponse were found to vary smoothly across the alloy systems. Band gap values obtained from the spectral sensitivity curves confirmed the parabolic variation of energy gaps as a function of the alloy concentration, as previously found in electrical conductivity and optical absorption measurements. The room temperature detectivity of the samples was between 2 × 105 and 8 × 106 cm (Hz)1/2 W−1 for wavelengths varying from 0.8 to 3.5 μ, depending on alloy composition.

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