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CZT Thesis

The CZT Thesis section features research theses focused on Cadmium Zinc Telluride (CZT) materials and their applications
Characterization of thermal neutron distribution of an Am–Be neutron source setup by CdZnTe detector
Date: July 12, 2025 | Author: Wenbao Jia | Hits: 97
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: 24
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: 36
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: 26
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: 35
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: 173
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: 43
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: 26
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: 43
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: 31
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: 60
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: 44
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: 15
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: 93
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 ...
Al doping and defect regulation of sputtered CdZnTe films based on Al–AlN transition layers
Date: July 5, 2025 | Author: Yue Shen | Hits: 201
CdZnTe films with less defects and high quality were fabricated on aluminum-rich AlN (Al–AlN) transition layers by RF magnetron sputtering technique. The Al doping and regulation effect on defect states, structure and photoelectrical performance of CdZnTe films were minutely investigated by XRD, HRTEM, SEM, XPS, Photoluminescence and Photoelectric characteristics. Results strongly suggested the self-doping process of Al from Al–AlN transition layers, which helped to compensate the defect d ...
CMOS readout FEE based TV-BLR module for CdZnTe pixel detectors in high count rate applications
Date: July 5, 2025 | Author: Mohammad Arif Sobhan Bhuiyan | Hits: 93
In this study, a time-variant baseline restorer (TV-BLR) circuit was designed and implemented to address the poor frequency selectivity issue in the shaping units of most state-of-the-art readout electronics for CdZnTe/CdTe detectors used in biomedical imaging applications. The proposed circuit improves image quality by canceling the artifacts that result from poor temporal and energy resolution in PET imaging. The proposed circuit consists of a Charge Sensitive Preamplifier (CSP) followed by ...
Development of travelling heater method for growth of detector grade CdZnTe single crystals
Date: July 4, 2025 | Author: S. Ganesamoorthy | Hits: 24
We report on the indigenous design and development of laboratory scale travelling heater method (THM) system to grow detector grade Cd0.9Zn0.1Te (CdZnTe) single crystals. THM system mainly consists of two-zone furnace with a tuneable temperature gradient (30–80 °C/cm), high precision translation (1–25 mm/day) and rotation (1–50 rpm) assemblies to meet the stringent conditions that are essential to grow detector grade CdZnTe single crystals. Further, a load cell in the THM system enables ...
Tailoring ohmic contact of CdZnTe based device using a ZnTe:Cu film interlayer
Date: July 4, 2025 | Author: Jian Huang | Hits: 22
ZnTe materials exhibit distinctive characteristics that render them exceptionally suitable for the utilization in circumventing the electrode contact issue for the CdZnTe based devices for photoelectric applications. This work employed the co-sputtering technique to fabricate ZnTe:Cu films, probing the influences of Copper (Cu) sputtering power on the film's structural, morphological, optical, and electrical properties. It is disclosed that the sputtering power of the Cu target leads to a ...
Count rate correction for pulse pileup in CdZnTe photon counting detectors
Date: July 3, 2025 | Author: Gangqiang Zha | Hits: 76
In the practical application of CdZnTe photon counting detectors, severe detector counting distortion can be caused by pulse pileup. A count rate correction method in this paper is proposed to solve this problem. In this method, the case where multi-photons are recorded by higher energy regions due to pulse pileup crossing the energy threshold is considered to calculate the true count rates under all energy bins. A verification method based on Poisson distribution is also proposed to evaluate ...
Photoluminescence of CdTe and CdZnTe compounds doped with 2% selenium
Date: July 3, 2025 | Author: Kihyun Kim | Hits: 28
The addition of 2 % of selenium in CdTe and CdZnTe (CZT) exhibited an additional acceptor-bound exciton in photoluminescence (PL). From the PL and inductively coupled plasma mass spectrometer (ICP/MS) analyses, the additional acceptor-bound exciton emission is associated with a Cu impurity in the relatively low-purity (5N) precursor CdSe starting material. In addition, thermal quenching of the acceptor/donor bound exciton emissions do not require a shift to any higher excited states or to the ...
Evolution features and optimization of interface shape during CdZnTe crystal growth using Vertical Gradient Freeze (VGF) technique
Date: July 2, 2025 | Author: Shangshu Li | Hits: 41
The growth of CdZnTe crystal suffers from poor yield due to the low thermal conductivity, and a convex growth interface is usually essential to grow large-volume CdZnTe single crystal because it can lessen the adverse interactions between the growing crystal and crucible wall. The growth of 90 mm diameter CdZnTe crystal by VGF technique has been investigated using experimental and simulation methods. The influences of the growth parameters (such as temperature gradient and growth rate) and the ...
Investigation of the CdZnTe (211) and (133) films grown on GaAs (211) controlled by temperature- Experiment and first-principles calculations
Date: July 2, 2025 | Author: Gangqiang Zha | Hits: 59
The origin and evolution of dual epitaxy in CdZnTe epilayer grown on GaAs substrates by close spaced sublimation has been studied, both (2 1 1) and (1 3 3) films are suitable for HgCdTe growth. And the effect of growth temperature on the orientation and crystalline quality of CdZnTe films has been investigated, more uniform orientation of adjoining growth islands in the growth of (1 3 3) film leads to a smoother surface with less threading dislocations and roughness. The interfacial properties ...
CdZnTe detectors tested at the DAΦNE collider for future kaonic atoms measurements
Date: July 1, 2025 | Author: Alessandro Scordo | Hits: 60
The SIDDHARTA-2 collaboration at the INFN Laboratories of Frascati (LNF) aims to perform important measurements on kaonic atoms. In parallel to the groundbreaking kaonic deuterium measurement, presently running on the DAΦNE collider at LNF, we plan to install additional detectors. The aim is to perform further kaonic atoms’ studies, taking advantage of the unique low energy and low momentum spread beam delivered by the at-rest decay of the meson. CdZnTe devices are ideal for detecting tran ...
Formation mechanism and elimination of needle defects on CdZnTe epitaxial films prepared by close-spaced sublimation
Date: July 1, 2025 | Author: Kun Cao | Hits: 28
Needle defects, one of the common surface defects in II-VI/III-VI semiconductor epitaxial films, negatively impact surface morphology and photoelectric properties of films limiting their application in solar cells, detectors, substrates, etc. Hence, the formation mechanism of needle defects in CdZnTe/GaAs system was investigated. It was found that needle defects have medium and low temperature adaptability. High resolution transmission electron microscope (HRTEM) characterization reveals needl ...
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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 Crystals 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.