An XPS study of bromine in methanol etching and hydrogen peroxide passivation treatments for cadmium zinc telluride radiation detectors

Babar, Shumaila; Sellin, P.J.; Watts, John F.; Baker, Mark

doi:10.1016/j.apsusc.2012.10.095

Cited by 32 publications

(9 citation statements)

References 17 publications

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“…The XPS binding energies of the elemental peaks considered in the current study are presented in table 1. The shift in peak positions of tellurium and oxygen upon oxidation (compared with bulk CdZnTe or OH − /H 2 O contamination, respectively) are well known [20,21] and these have also been considered.…”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%

A multi-technique characterization of electroless gold contacts on single crystal CdZnTe radiation detectors

Bell

Baker

Chen

et al. 2013

J. Phys. D: Appl. Phys.

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Section: X-ray Photoelectron Spectroscopymentioning

confidence: 99%

A multi-technique characterization of electroless gold contacts on single crystal CdZnTe radiation detectors

Bell

Baker

Chen

et al. 2013

J. Phys. D: Appl. Phys.

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“…A typical etching chemical is 1% to 2% bromine-methanol solution [12], [13]. Surface passivation of the CZT wafer is used to minimize surface oxidation and increase the shelf and operational life of the detector [14], [15]. Reduction of the surface roughness of CZT wafers from 9.25 nm root mean square (RMS) for mechanical polishing to 2.50 nm RMS after etching in 2% bromine-methanol solution has been reported [12].…”

Section: Introductionmentioning

confidence: 97%

Comparative study on the effects of chemical treatments on CdZnTe nuclear detectors

Egarievwe

Okwechime

Hossain

et al. 2014

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

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Room temperature semiconductor detectors such as cadmium zinc telluride (CdZnTe) are often subject to surface damage during fabrication processes, thus affecting detector performance. The surface defects are usually removed through mechanical and chemical polishing, and passivation processes. This paper compares the effects of two surface passivation chemical solutions on CdZnTe detectors. The two chemicals studied are ammonium fluoride in hydrogen peroxide (NH 4 F + H 2 O 2 + H 2 O) and potassium hydroxide in hydrogen peroxide (0.1 g of KOH + 10 ml of 30% H 2 O 2 ) solutions. X-ray photoelectron spectroscopy analysis showed that the NH 4 F-based solution is more effective at converting Te species on the CZT wafer surfaces into a more stable TeO 2 layer, with values of 4.90 and 5.34 for the Te3d 3/2 O 2 /Te3d 3/2 and Te3d 5/2 O 2 /Te3d 5/2 peakheight ratios respectively, compared to the KOH-based solution which has 1.25 and 1.19 respectively. Analysis of the 59.5-keV peak of Am-241 showed that the sample passivated with the NH 4 F-based solution has a better energy resolution (FWHM = 9.83%) compared to the one passivated with the KOH-based solution (FWHM = 14.60%).

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“…The chemical treatment of the CdTe-based detector wafers produces a smoother and more stoichiometric surface after polishing [20]. It also minimizes the oxidation of the wafer surfaces, thus leading to an increased shelf life of the detector [21,22].…”

Section: Introductionmentioning

confidence: 99%

Ammonium Fluoride Passivation of CdZnTeSe Sensors for Applications in Nuclear Detection and Medical Imaging

Egarievwe

Roy

Goree

et al. 2019

Sensors

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Cadmium zinc telluride selenide (Cd1−xZnxTe1−ySey or CZTS) is one of the emerging CdTe-based semiconductor materials for detecting X- and gamma-ray radiation at or near room temperature (i.e., without cryogenic cooling). Potential applications of CZTS sensors include medical imaging, X-ray detection, and gamma-ray spectroscopy. Chemical passivation of CZTS is needed to reduce the conductivity of Te-rich surfaces, which reduces the noise and improves the device performance. In this study, we focus on the effect of surface passivation of CZTS using a 10% aqueous solution of ammonium fluoride. The effects of the chemical treatment were studied on the leakage current, charge transport measured as the electron mobility-lifetime (µτ) product, and the spectral resolution measured as the full-width at half-maximum (FWHM) of specific peaks. After passivation, the leakage current increased and began to decrease towards pre-passivation levels. The energy resolutions were recorded for eight applied voltages between −35 V and −200 V. The results showed an average of 25% improvement in the detector’s energy resolution for the 59.6 keV gamma peak of Am-241. The electron µτ product was unchanged at 2 × 10−3 cm2/V. These results show that ammonium fluoride is effective for chemical passivation of CZTS detectors.

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An XPS study of bromine in methanol etching and hydrogen peroxide passivation treatments for cadmium zinc telluride radiation detectors

Cited by 32 publications

References 17 publications

A multi-technique characterization of electroless gold contacts on single crystal CdZnTe radiation detectors

A multi-technique characterization of electroless gold contacts on single crystal CdZnTe radiation detectors

Comparative study on the effects of chemical treatments on CdZnTe nuclear detectors

Ammonium Fluoride Passivation of CdZnTeSe Sensors for Applications in Nuclear Detection and Medical Imaging

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