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CZT Thesis

The CZT Thesis section features research theses focused on Cadmium Zinc Telluride (CZT) materials and their applications
Effects of annealing in Te2 atmosphere on photoelectric properties and carrier transport properties of CdZnTe films
Date: July 17, 2025 | Author: Kun Cao | Hits: 29
CdZnTe (CZT) epitaxial films were deposited on GaAs substrates by closed spaced sublimation. In order to reduce the adverse effects of point defects and dislocations in the film on its properties, CZT films were annealed at 400 °C in Te2 atmosphere at different times. The I–V test and energy spectrum show that the resistivity of CZT films increased from 109 Ω cm to 1010 Ω cm, and the electron mobility lifetime product (μτ)e increased from 10−5 cm2 V−1 to 10−4 cm2 V−1. According ...
Monte-Carlo simulation for detecting neutron and gamma-ray simultaneously with CdZnTe half-covered by gadolinium film
Date: July 17, 2025 | Author: B. Park | Hits: 22
Neutron is an indirectly ionizing particle without charge, which is normally measured by detecting reaction products. Neutron detection system based on measuring gadolinium-converted gamma-rays is a good way to monitor the neutron because the representative prompt gamma-rays of gadolinium have low energies (79, 89, 182, and 199 keV). Low energy gamma-rays and their high attenuation coefficient on materials allow the simple design of a detector easier to manufacture. Thus, we designed a cadmium ...
Electro and electro-photo plasticity of CdZnTeSe and CdZnTe
Date: July 16, 2025 | Author: Václav Dědič | Hits: 31
We studied the influence of applied bias on of the Vickers microhardness HV 0.025 of CdZnTeSe and CdZnTe semi-insulating samples without and with the illumination of light at 870 nm. We observed that a small applied bias results in the hardening of the material. The effect is strongest at a bias of ± 0.5 V and is further strengthened by additional illumination. We suggest that the observed positive electro and electro-photo plastic effects in CdZnTeSe and CdZnTe can be explained by an increas ...
Spectrally-dependent positive and negative photo-plastic effects in CdZnTe and CdZnTeSe
Date: July 16, 2025 | Author: Václav Dědič | Hits: 27
We studied the Vickers microhardness HV0.025 of CdZnTe and CdZnTeSe samples upon illumination with quasi-monochromatic light with wavelengths ranging between 750 and 1540 nm. We observed that light with a wavelength close to or above the bandgap of the samples results in a positive photo-plastic effect (hardening), and light in the spectral range well below the band gap can lead both to positive or negative effects depending on the parameters of deep levels in the bandgap. We performed measure ...
Production of detector grade CdZnTe crystal with VGF furnace by analyzing segregation of Zn and In
Date: July 15, 2025 | Author: Mustafa Ünal | Hits: 33
Production of CdZnTe crystals for radiation detector applications through Bridgman and Vertical Gradient Freeze (VGF) techniques is challenging in many aspects. Due to the structural characteristics of CdZnTe, it is not possible to obtain a large single crystalline ingots from the melt growth technique. In addition, the segregation of dopants and Zn decrease the yield significantly. In order to achieve detector-grade CdZnTe crystals, zinc segregation behavior should be fully understood, and op ...
Study on relaxation phenomenon of CdZnTe photon counting detectors in X-ray imaging
Date: July 15, 2025 | Author: Yingrui Li | Hits: 12
During X-ray scanning imaging, the X-ray dose received by CdZnTe photon counting detectors varies dynamically because of the different absorption coefficients that occur at different locations in the object being imaged. This paper explores the phenomenon of count rate relaxation in CdZnTe detectors during X-ray dose mutations and studies the intrinsic relationship of this phenomenon with the polarization effect. The characterization of the count rate relaxation processes of CdZnTe detectors a ...
Feasibility study of CdZnTe and CdZnTeSe based high energy X-ray detector using linear accelerator
Date: July 14, 2025 | Author: Jeongho Kim | Hits: 48
CdZnTeSe (CZTS) has attracted attention for applications in X- and gamma-ray detectors owing to its improved properties compared to those of CdZnTe (CZT). In this study, we grew and processed single crystals of CZT and CZTS using the Bridgeman method to confirm the feasibility of using a dosimeter for high-energy X-rays in radiotherapy. We evaluated their linearity and precision using the coefficient of determination (R2) and relative standard deviation (RSD). CZTS showed sufficient RSD values ...
Morphology-property relationships of CdZnTe films prepared via radio frequency magnetron sputtering
Date: July 14, 2025 | Author: Dongmei Zeng | Hits: 12
The polycrystalline CdZnTe films are promising material for fabrication of X-ray detection and solar cells. In this study, a pebble-like grain, hexagonal grain and worm-like grain of CdZnTe films were prepared via radio frequency magnetron sputtering. The morphology and properties of CdZnTe films were then characterized using atomic force microscopy, 2-D grazing-incidence wide-angle X-ray scattering, Raman spectra, transmission spectra and current–voltage curves. Accordingly, the CdZnTe crys ...
The Growth Pits Filling Mechanism of CdZnTe Epitaxial Film Prepared by Close-Spaced Sublimation Based on the First-Principles Calculation
Date: July 13, 2025 | Author: Kun Cao | Hits: 49
The preparation of high quality II-VI semiconductor single crystal still is a challenging task. The II-VI ternary compound Cd1-xZnxTe is an outstanding candidate for room temperature nuclear radiation detectors. Therefore, the epitaxial mechanism of its film is profound to clarify for accurate growth regulation and quality improvement. However, determining the essence of epitaxial growth remains challenge only using experiments to explore the effects of growth conditions on film epitaxy. In th ...
Capability demonstration of a 3D CdZnTe detector on a high-altitude balloon flight
Date: July 13, 2025 | Author: Sara Abraham | Hits: 10
In collaboration between the University of Michigan and Los Alamos National Laboratory, a 3D position-sensing CdZnTe (CZT) detector prototype was built and integrated into a high-altitude balloon platform to evaluate its performance in a space-like mixed-radiation environment. The detector prototype, Orion Eagle, was designed to operate in near-vacuum environments without any temperature regulation. Orion Eagle was hand-launched from NASA’s Columbia Scientific Balloon Facility (CSBF) at Fort ...
Characterization of thermal neutron distribution of an Am–Be neutron source setup by CdZnTe detector
Date: July 12, 2025 | Author: Wenbao Jia | Hits: 35
Owing to the developments in prompt gamma neutron activation analysis (PGNAA) and prompt gamma ray activation imaging (PGAI), it is necessary to develop an online thermal neutron distribution measurement method. The CdZnTe detector is considered as an alternative thermal neutron detector because of its high thermal neutron capture cross section. In this study, the thermal neutron field of an 241Am–Be neutron source was determined by CdZnTe detector. The intrinsic neutron detection efficiency ...
Using 3D position sensitivity to reveal response non-uniformities in CdZnTe, TlBr, and CsPbBr3 detectors
Date: July 12, 2025 | Author: A.E. Bolotnikov | Hits: 7
Position sensitivity enables the correction of response non-uniformities in room-temperature semiconductor detectors caused by crystal defects and other factors. It can also be used to pinpoint the exact location of crystal defects responsible for the response variations. This work describes a technique for revealing and visualizing the detector regions affecting the charge collection efficiency in CdZnTe (CZT), TlBr, and CsPbBr3 detectors configured as position-sensitive virtual Frisch-grid ( ...
Evaluation of electron lifetime for Te inclusions free CdZnTe
Date: July 11, 2025 | Author: Kihyun Kim | Hits: 9
Te secondary phase defects are known as major obstacle for improving charge carriers transport properties of CdTe compounds material. The enhanced detector performance was reported for Te inclusions free CZT detector implemented through two-step annealing (i.e., first in Cd and second in Te). We applied the time-of-flight (TOF) technique to measure the electron lifetime in as-grown and two-step annealed CZT material. TOF has several advantages over Hecht equation fitting such as independence o ...
Preparation and characterization of large-sized CdZnTe epitaxial single crystal
Date: July 11, 2025 | Author: Gangqiang Zha | Hits: 18
CdZnTe (CZT) epitaxial single crystal with a diameter of 2 inches and a thickness exceeding 1 mm was prepared by the closed spaced sublimation. In order to test the uniformity of the large-sized CZT epitaxial single crystal, the composition, crystalline quality, X-ray response performance and carrier transport property of the central and edge parts of the CZT crystal were characterized. The morphology images show that different areas have flat surfaces with dislocation densities between 3.5 × ...
Effect of sub-grain boundaries in CdZnTe on HgCdTe film grown by molecular beam epitaxy
Date: July 10, 2025 | Author: J.C. Kong | Hits: 10
HgCdTe films grown by molecular beam epitaxy (MBE) are essential for creating high-performance infrared focal plane arrays (IRFPAs) like dual band detectors, high operating temperature (HOT) detectors, and avalanche photodiode (APD) detectors. CdZnTe is recognized as the optimal substrates for growing high crystal quality HgCdTe due to its lattice matching, which is adjusted by selecting the Zn mole fraction. However, defects like grain boundaries, twins, inclusions, dislocations, and sub-grai ...
Optimizing the temperature gradient for CdZnTe crystal growth using the vertical Bridgman–Stockbarger method
Date: July 10, 2025 | Author: Bing Yan | Hits: 127
CdZnTe (CZT) is considered an ideal material for the growth of HgCdTe (MCT) epitaxial layers and nuclear detection devices. The crystal quality of CZT is the key factor in the MCT-based infrared plane array and the performance of nuclear devices. Herein, we report the growth of CZT by optimizing the temperature gradient vertical Bridgman–Stockbarger method. The crystalline character of the obtained CZT has been examined using optical microscopy, IR transmission microscopy, high-resolution X- ...
Effect of passivation sequence on the performance of planar CdZnTe detectors
Date: July 9, 2025 | Author: Jijun Zhang | Hits: 12
Passivation is usually used to reduce the leakage current between contacts of CdZnTe devices with pixel electrodes. For CdZnTe devices with planar electrodes, different passivation sequences and passivation regions result in two different device structures. In this paper, two different passivation sequences were used to treat the etched CdZnTe: depositing electrodes followed by passivation, and passivation followed by depositing electrodes, the difference they caused was whether the region bel ...
Tailoring the defects and resistivity in CdZnTe single crystal via one-step annealing with CdTe compound
Date: July 9, 2025 | Author: Siwei Tang | Hits: 11
Defects deteriorate the optical and electronic properties of the cadmium zinc telluride (CZT) single crystal. However, the growth of defects, such as vacancies and precipitation, could not be avoided in the industrial-grade preparation of CZT single crystal. Therefore, it is crucial to explore ways to eliminate defects after growth. This paper employs one-step heat treatment with the CdTe compound as an annealing atmosphere source. After annealing, some large-size Te inclusions are eliminated ...
CdZnTe thin films as proficient absorber layer candidates in solar cell devices: a review
Date: July 8, 2025 | Author: M. S. Dhaka | Hits: 29
The energy crisis has become the greatest global challenge in this era of cutting-edge technology, driving researchers to utilize novel renewable energy resources via solar cells to satisfy the energy demand. To date, the popular silicon solar cell technology has achieved a power conversion efficiency (PCE) of more than 26% at the laboratory scale and is superior to other technologies with a commercial panel efficiency in the range of 14–20%; however, it is very costly. Alternatively, organi ...
Improvement of crystallinity of CdZnTe epilayers on GaSb substrates by ZnTe buffer layer
Date: July 8, 2025 | Author: Wanqi Jie | Hits: 15
Thick CdZnTe epitaxial film is a promising alternative for X-ray detectors, especially in the case of large-area imaging application. One of the key issues in growing thick heteroepitaxial film with high crystallinity is to reduce the mismatch dislocations that appear at the interface between CdZnTe epilayer and the substrate. In this paper, we prepared CdZnTe films without and with ZnTe buffer layers on GaSb (001) substrates by the closed space sublimation. All preparation conditions for ZnTe ...
Achieving stable photodiode characteristics under ionizing radiation with a self-adaptive nanostructured heterojunction CNWs-CdZnTe
Date: July 7, 2025 | Author: Viktor V. Brus | Hits: 24
This study proposed self-adaptive nanostructured heterojunction UV-VIS-NIR photodiodes carbon nanowalls (CNWs)/cadmium zinc telluride (CdZnTe) exhibiting stable photoelectric characteristics under ionizing radiation conditions. We carried out a comprehensive analysis of the impact of proton radiation with an energy of 1.5 MeV and a total fluence of 1012 protons/cm2 on the properties of CNWs and CdZnTe functional layers, as well as on the main photodiode characteristics of the CNWs/CdZnTe heter ...
Regulation of Te oxide layer on a CdZnTe film for adjusting surface contact of a CdZnTe-based device
Date: July 7, 2025 | Author: Jian Huang | Hits: 31
The control of the interface states between the electric contacts and semiconductor is a key issue to develop high-performance functional devices. The polishing, passivation, and oxidation processes can optimize the surface states of the CdZnTe (CZT) film to improve the contact characteristics with the electrode and tailor the resistivity to control the electrical performance. In this work, a serial of surface treatments including mechanical polishing (MP) + chemical polishing (CP) + surface p ...
Growth of CdZnTe (211) epilayers on GaAs by close spaced sublimation as an alternative substrate for HgCdTe growth
Date: July 6, 2025 | Author: Kun Cao | Hits: 8
Cd0.96Zn0.04Te crystals are perfect substrates for epitaxial growth of HgCdTe films due to good lattice matching, but they are limited by cost factors. To grow a replacement substrate for the subsequent growth of low-cost, high-yield HgCdTe IR materials, CdZnTe epitaxial films have been fabricated by close-spaced sublimation on GaAs substrates, and the effect of substrate temperature on the crystalline quality of CdZnTe films has been investigated. The results of EBSD and TEM indicate that the ...
Radiation damage of 2×2×1cm3 pixelated CdZnTe due to high-energy protons
Date: July 6, 2025 | Author: Daniel Shy | Hits: 44
Pixelated CdZnTe detectors are a promising imaging-spectrometer for gamma-ray astrophysics due to their combination of relatively high energy resolution with room temperature operation negating the need for cryogenic cooling. This reduces the size, weight, and power requirements for telescope-based radiation detectors. Nevertheless, operating CdZnTe in orbit will expose it to the harsh radiation environment of space. This work, therefore, studies the effects of 61 MeV protons on 2x2x1CM3 pixel ...
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CdZnTe Association (CdZnTe.com) is a nonprofit website dedicated to Cadmium Zinc Telluride (CZT) technology. It serves as a comprehensive platform for sharing knowledge, research advancements, and practical applications related to CZT materials and detectors. The site aims to support scientists, engineers, and students by providing access to technical resources, publications, and community-driven insights, fostering collaboration and innovation within the CZT research and development community.