A new process for synthesizing high-purity stoichiometric cadmium telluride

Zappettini, A.; Görög, T.; Zha, M.; Zanotti, L.; Zuccalli, G.; Paorici, C.

doi:10.1016/s0022-0248(00)00042-7

Cited by 32 publications

(16 citation statements)

References 11 publications

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“…The CIGS targets were obtained by a high temperature and Energies 2016, 9, 207 4 of 11 moderate pressure synthesis process starting from elemental species (Cu, In, Ga, and Se with 5 N purity). This process, previously developed for the synthesis of high-purity polycrystalline targets of CdTe [14], is specifically developed to widen the window of optimum beam energy values. Different electron beam sources and growth conditions are being explored to move the window towards large deposition rates as part of the effort to make the process compatible with industrial scale production of CIGS solar cells.…”

Section: Resultsmentioning

confidence: 99%

Progress on Low-Temperature Pulsed Electron Deposition of CuInGaSe2 Solar Cells

et al. 2016

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Abstract:The quest for single-stage deposition of CuInGaSe 2 (CIGS) is an open race to replace very effective but capital intensive thin film solar cell manufacturing processes like multiple-stage coevaporation or sputtering combined with high pressure selenisation treatments. In this paper the most recent achievements of Low Temperature Pulsed Electron Deposition (LTPED), a novel single stage deposition process by which CIGS can be deposited at 250˝C, are presented and discussed. We show that selenium loss during the film deposition is not a problem with LTPED as good crystalline films are formed very close to the melting temperature of selenium. The mechanism of formation of good ohmic contacts between CIGS and Mo in the absence of any MoSe 2 transition layers is also illustrated, followed by a brief summary of the measured characteristics of test solar cells grown by LTPED. The 17% efficiency target achieved by lab-scale CIGS devices without bandgap modulation, antireflection coating or K-doping is considered to be a crucial milestone along the path to the industrial scale-up of LTPED. The paper ends with a brief review of the open scientific and technological issues related to the scale-up and the possible future applications of the new technology.

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Section: Resultsmentioning

confidence: 99%

Progress on Low-Temperature Pulsed Electron Deposition of CuInGaSe2 Solar Cells

et al. 2016

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“…10 After synthesis, the charge was heat-treated at about 870°C to obtain a reproducible charge composition 11 and then charged into a quartz ampoule. The ampoule was closed only when the charge was not covered by a boron oxide pellet (water content 200 ppm, 99.9995% nominal purity).…”

Section: Methodsmentioning

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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“…[9][10][11] both by Bridgman and PVT techniques. Hall effect measurements were performed using the Van der Pauw configuration.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we obtained high purity semi-insulating CdTe by the use of a many steps process consisting in (i) synthesis by a high pressure technique [9], (ii) stoichiometry optimisation of the polycrystals [10], and (iii) growth by Bridgman and physical vapour transport (PVT) [11]. We also showed that, given a low background impurity content, the resistivity of the samples was mainly controlled by the stoichiometry [12].…”

Section: Introductionmentioning

confidence: 99%

Deep level characterization of undoped CdTe crystals

Gombia

Bissoli

Zha

et al. 2003

phys. stat. sol. (c)

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Cadmium telluride crystals have been prepared using innovative techniques for the synthesis and purification of the feed charge. The growth of low impurity content CdTe crystals was performed by both physical vapour transport and Bridgman techniques. It was found that the resistivity of the obtained crystals was strongly connected with their stoichiometry. The characterization of the main deep levels in semiconducting and semi-insulating materials, carried out by capacitance and current techniques, is reported.

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A new process for synthesizing high-purity stoichiometric cadmium telluride

Cited by 32 publications

References 11 publications

Progress on Low-Temperature Pulsed Electron Deposition of CuInGaSe2 Solar Cells

Progress on Low-Temperature Pulsed Electron Deposition of CuInGaSe2 Solar Cells

On the Role of Boron in CdTe and CdZnTe Crystals

Deep level characterization of undoped CdTe crystals

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