Inhomogeneous resistivity and its effect on CdZnTe-based radiation detectors operating at high radiation fluxes

Zázvorka, Jakub; Pekárek, Jakub; Grill, R.; Belas, E.; Ridzoňová, Katarína; Pipek, Jindřich; Franc, J.

doi:10.1088/1361-6463/ab23e3

Cited by 10 publications

(3 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 8 illustrates the resistivity results of F1-02 and F1-03 from Contactless Resistivity Mapping. As shown in the figure, the resistivity over the entire areas of the two samples was found to be in the range of 0.8-9 × 10 9 Ωcm, which is consistent with high quality CZT materials [25][26][27]. The resistivities of F1-02 and F1-03 are in the order of 3 × 10 9 Ωcm and 1 × 10 9 Ωcm, respectively.…”

Section: Electrical Performancesupporting

confidence: 69%

Characterization of Structural Defects in (Cd,Zn)Te Crystals Grown by the Travelling Heater Method

Zou¹,

Fauler²,

Senchenkov

et al. 2021

Crystals

View full text Add to dashboard Cite

Structural defects and compositional uniformity remain the major problems affecting the performance of (Cd, Zn)Te (CZT) based detector devices. Understanding the mechanism of growth and defect formation is therefore fundamental to improving the crystal quality. In this frame, space experiments for the growth of CZT by the Travelling Heater Method (THM) under microgravity are scheduled. A detailed ground-based program was performed to determine experimental parameters and three CZT crystals were grown by the THM. The structural defects, compositional homogeneity and resistivity of these ground-based crystals were investigated. A ZnTe content variation was observed at the growth interface and a high degree of stress associated with extensive dislocation networks was induced, which propagated into the grown crystal region according to the birefringence and X-ray White Beam Topography (XWBT) results. By adjusting the growth parameters, the ZnTe variations and the resulting stress were efficiently reduced. In addition, it was revealed that large inclusions and grain boundaries can generate a high degree of stress, leading to the formation of dislocation slip bands and subgrain boundaries. The dominant defects, including grain boundaries, dislocation networks and cracks in the interior of crystals, led to the resistivity variation in the crystals. The bulk resistivity of the as-grown crystals ranged from 109 Ωcm to 1010 Ωcm.

show abstract

Section: Electrical Performancesupporting

confidence: 69%

Characterization of Structural Defects in (Cd,Zn)Te Crystals Grown by the Travelling Heater Method

Zou¹,

Fauler²,

Senchenkov

et al. 2021

Crystals

View full text Add to dashboard Cite

show abstract

“…These large-volume, good-uniformity CdZnTe photon counting detectors, which can detect a photon flux in the order of a hundred million mm −2 s −1 , are necessary for many applications such as medical and industrial imaging [8,9]. Although such high-flux CdZnTe detectors have been reported [10], it is still a challenge to achieve large-scale commercial applications, primarily due to the material defects which can lead to the polarization effect [11][12][13][14][15][16]. Under high X-ray flux conditions, excessive positive space charges formed by trapped holes build up inside the detector, which have an opposite effect on the externally applied voltage and ultimately result in a non-uniform electric field and catastrophic device failure.…”

Section: Introductionmentioning

confidence: 99%

Effect of Deep-Level Defects on the Performance of CdZnTe Photon Counting Detectors

Zha

Wei

et al. 2020

Sensors

View full text Add to dashboard Cite

The effect of deep-level defects is a key issue for the applications of CdZnTe high-flux photon counting devices of X-ray irradiations. However, the major trap energy levels and their quantitive relationship with the device’s performance are not yet clearly understood. In this study, a 16-pixel CdZnTe X-ray photon counting detector with a non-uniform counting performance is investigated. The deep-level defect characteristics of each pixel region are analyzed by the current–voltage curves (I–V), infrared (IR) optical microscope photography, photoluminescence (PL) and thermally stimulated current (TSC) measurements, which indicate that the difference in counting performance is caused by the non-uniformly distributed deep-level defects in the CdZnTe crystals. Based on these results, we conclude that the CdZnTe detectors with a good photon counting performance should have a larger Te cd 2 + and Cd vacancy-related defect concentration and a lower A-center and Tei concentration. We consider the deep hole trap Tei, with the activation energy of 0.638–0.642 eV, to be the key deep-level trap affecting the photon counting performance. In addition, a theoretical model of the native defect reaction is proposed to understand the underlying relationships of resistivity, deep-level defect characteristics and photon counting performance.

show abstract

“…Understanding the relation between photocarrier transport dynamics and material's electrical properties plays a key role in optimizing the performance of various photoelectric devices. For example, high resistivity is an essential requirement for semiconductors used in certain applications, such as radiation detectors [1] and photoconductive switches [2]. However, a high resistivity semiconductor could exhibit generically different carrier transport behaviors from that of a low resistivity one.…”

Section: Introductionmentioning

confidence: 99%

Photocarrier transport dynamics in lifetime and relaxation regimes of semiconductors containing traps

Zhang

et al. 2019

Mater. Res. Express

View full text Add to dashboard Cite

High resistivity semiconductors used in various optoelectronic devices, such as radiation detectors and photoconductive switches, usually require electrical compensation involving deep level defects, which are also closely related to the photocarrier transport dynamics. In this paper, one-dimensional spatiotemporal evolution of photocarriers is numerically investigated in semiconductors containing traps. After introducing a high concentration of traps, the dynamics can be divided into three categories: relaxation, lifetime and intermediate regimes. Photocarriers will separate in the relaxation regime and transport ambipolarly in the lifetime regime. Captured space charges enhance the internal electric field between photogenerated electrons and holes, thus reduce carriers' transport velocities in all three regimes. Storage of photocarriers in traps also weakens the majority carrier depletion in the relaxation regime, and could pin the majority carriers to the injection spot in the lifetime regime. In the intermediate regime, both semiconductor type and relative magnitudes of the dielectric relaxation time and carrier lifetimes determine the photocarrier transport behavior. By combining the threeenergy-level compensation model and the trap-mediated recombination model, the criterion for different regimes and photocarrier transport dynamics are investigated in deep donor compensated CdTe semiconductors.

show abstract

Inhomogeneous resistivity and its effect on CdZnTe-based radiation detectors operating at high radiation fluxes

Cited by 10 publications

References 24 publications

Characterization of Structural Defects in (Cd,Zn)Te Crystals Grown by the Travelling Heater Method

Characterization of Structural Defects in (Cd,Zn)Te Crystals Grown by the Travelling Heater Method

Effect of Deep-Level Defects on the Performance of CdZnTe Photon Counting Detectors

Photocarrier transport dynamics in lifetime and relaxation regimes of semiconductors containing traps

Contact Info

Product

Resources

About