Full encapsulated CdZnTe crystals by the vertical Bridgman method

Zha, M.; Zappettini, A.; Calestani, Davide; Marchini, L.; Zanotti, L.; Paorici, C.

doi:10.1016/j.jcrysgro.2007.11.230

Cited by 39 publications

(20 citation statements)

References 13 publications

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“…In an effort to develop a procedure to grow ingots with high purity and large single grains, a new Bridgman configuration for growth of CZT crystals 5,6 was studied in our laboratories. In contrast to the standard vertical Bridgman technique, the crystal is grown in an open ampoule, melt decomposition being prevented by use of a boron oxide layer and an opportune counterpressure of inert gas.…”

Section: Introductionmentioning

confidence: 99%

On the Role of Boron in CdTe and CdZnTe Crystals

Pavesi

Marchini

Zha

et al. 2011

Journal of Elec Materi

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It is well known that group III elements act as donors if they play a substitutional role at the metallic site in II-tellurides; nevertheless, several studies report both on the creation of complexes with vacancies, named A-centers, and on the involvement in self-compensation mechanisms, especially for indium. The boron concentration in II-tellurides is negligible, and its contribution to transport mechanisms has not been studied yet. For the last few years the authors have been developing a new technique to grow CdZnTe by the vertical Bridgman technique, taking advantage of encapsulation by means of boron oxide. In this way, crystals characterized by large single grains, low etch pit density, and high resistivity have been obtained. Recently, x-ray detectors with state-of-the-art performance have been produced from such crystals. Boron contamination, as a consequence of this growth method, is quite low but at least one order of magnitude above values obtained with other growth techniques. Besides being a low-cost technique which is also suitable for largescale mass production, the encapsulated vertical Bridgman technique is quite useful to prevent dislocations, grain boundaries, and stacking faults; for these reasons, careful characterization was performed to understand the effect of boron both on the electrical properties and on the spectroscopic performance of the final crystals. Our characterization is mainly based on low-temperature photoluminescence in addition to electrical current-voltage measurements, photostimulated current, and x-ray spectroscopy. The results indicate that boron behaves like other group III elements; in fact, boron forms a complex that does not affect the good performance of our x-ray detectors, even if it shows some properties which are typical of A-centers.

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Section: Introductionmentioning

confidence: 99%

On the Role of Boron in CdTe and CdZnTe Crystals

Pavesi

Marchini

Zha

et al. 2011

Journal of Elec Materi

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“…The idea is to study the response of pixel detectors based on CdZnTe grown by boron oxide vertical Bridgman method to operate in the low-medium energy range (10 keV-160 keV) for applications such as security, food inspection, industrial monitoring. [2,4]. CdZnTe polycrystalline material is obtained by direct synthesis of high purity elements [5].…”

Section: Introductionmentioning

confidence: 99%

“…Thanks to the use of boron oxide, it is not necessary to seal the growth ampoule, being material evaporation prevented by boron oxide itself and by a moderate argon pressure (about 5 bars). This growth procedure presents several advantages: i) there is no risk of ampoule explosion, ii) there is no free volume, so that material stoichiometry is preserved, iii) a liquid boron oxide layer fully surrounds the quartz ampoule so that the contact between the quartz ampoule and the growing crystal is prevented [2,4].…”

Section: Introductionmentioning

confidence: 99%

High energy resolution pixel detectors based on boron oxide vertical Bridgman grown CdZnTe crystals

Zappettini

Macera

Benassi

et al. 2014

2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)

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CdZnTe crystals are used for the realization of Xray\ud detectors. In particular, pixel detectors can be exploited for\ud many application fields such as medical diagnostics, security, and\ud industrial inspection. In the last years, CdZnTe crystals have\ud routinely been grown by the boron oxide encapsulated vertical\ud Bridgman technique. In this work, it is shown that linear array\ud detectors have been prepared based on this material. The\ud detectors show low leakage current and have been coupled to a\ud specifically designed research-grade low noise ASIC. The\ud detectors show good spectroscopic characteristics and no\ud polarization effects, meeting the requirements for the realization\ud of high throughput, multi-energy scanners

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“…In fact a huge number of applications, such as X-and Gamma-Ray detectors [1][2][3][4] e.g for medical imaging, security devices, etc. [4] are based on the high atomic number and high density of CdTe [5].…”

Section: Introductionmentioning

confidence: 99%