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

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3271 ◽  
Author(s):  
Stephen U. Egarievwe ◽  
Utpal N. Roy ◽  
Carmella A. Goree ◽  
Benicia A. Harrison ◽  
Jeanette Jones ◽  
...  
Keyword(s):  
Medical Imaging ◽  
Leakage Current ◽  
Gamma Ray ◽  
Surface Passivation ◽  
Ammonium Fluoride ◽  
Cryogenic Cooling ◽  
Gamma Peak ◽  
Potential Applications ◽  
Chemical Passivation ◽  
Effect Of Surface

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.

scholarly journals ESR white paper: blockchain and medical imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
◽  
Elmar Kotter ◽  
Luis Marti-Bonmati ◽  
Adrian P. Brady ◽  
Nandita M. Desouza
Keyword(s):  
Medical Imaging ◽  
Image Data ◽  
Distributed Database ◽  
Relevant Information ◽  
White Paper ◽  
Imaging Data ◽  
Data Set ◽  
Blockchain Technology ◽  
Potential Applications ◽  
Basic Technology

AbstractBlockchain can be thought of as a distributed database allowing tracing of the origin of data, and who has manipulated a given data set in the past. Medical applications of blockchain technology are emerging. Blockchain has many potential applications in medical imaging, typically making use of the tracking of radiological or clinical data. Clinical applications of blockchain technology include the documentation of the contribution of different “authors” including AI algorithms to multipart reports, the documentation of the use of AI algorithms towards the diagnosis, the possibility to enhance the accessibility of relevant information in electronic medical records, and a better control of users over their personal health records. Applications of blockchain in research include a better traceability of image data within clinical trials, a better traceability of the contributions of image and annotation data for the training of AI algorithms, thus enhancing privacy and fairness, and potentially make imaging data for AI available in larger quantities. Blockchain also allows for dynamic consenting and has the potential to empower patients and giving them a better control who has accessed their health data. There are also many potential applications of blockchain technology for administrative purposes, like keeping track of learning achievements or the surveillance of medical devices. This article gives a brief introduction in the basic technology and terminology of blockchain technology and concentrates on the potential applications of blockchain in medical imaging.

ZnO Nanoparticles, Nanorods, Hexagonal Plates and Nanosheets Produced by Polyol Route and the Effect of Surface Passivation by Acetate Molecules on Optical Properties

2019 ◽  
Vol 48 (10) ◽  
pp. 6437-6445
Author(s):  
Eduardo F. Barbosa ◽  
Jaqueline A. Coelho ◽  
Edna R. Spada ◽  
Daniel R. B. Amorim ◽  
Livia M. C. Souza ◽  
...  
Keyword(s):  
Optical Properties ◽  
Zno Nanoparticles ◽  
Surface Passivation ◽  
Effect Of Surface

A New Method For The Electronic And Chemical Passivation Of GaAs Surfaces Using CS2

1995 ◽  
Vol 406 ◽  
Author(s):  
Ju-Hyung Lee ◽  
Yanzhen Xu ◽  
Veronica A. Burrows ◽  
Paul F. McMillan
Keyword(s):  
Surface Passivation ◽  
Passivation Layer ◽  
Semiconductor Diode ◽  
Photoluminescence Intensity ◽  
Atmospheric Conditions ◽  
Metal Insulator ◽  
Insulating Layer ◽  
Capacitance Voltage ◽  
Chemical Passivation ◽  
Homogeneous Film

AbstractA new GaAs surface passivation method, CS2 treatment at moderate temperature was developed for effective passivation of GaAs surfaces. The CS2 treatment of GaAs surfaces at 350°C and 10 atm leads to deposition of a homogeneous film, with a thickness of several hundred Å. The passivation layer thus produced causes a significant enhancement in room temperature photoluminescence intensity and the passivation effect of the sulfide film was confirmed by Raman spectroscopy. The passivation layer remained electrically and chemically stable over a period of nine months under ambient atmospheric conditions. In-depth Auger electron spectroscopy (AES) revealed that the carbon and oxygen content in the film was negligible, whereas sulfur was uniformly distributed throughout the film. A metal-insulator-semiconductor diode whose insulating layer is produced by the CS2 treatment shows well-defined accumulation and depletion regions in its capacitance-voltage (CV) characteristics with low hysteresis.

APPLICATION OF EPITAXIAL UNIPOLAR BARRIERS TO REDUCE NOISE CURRENTS IN PHOTODETECTORS

2011 ◽  
Vol 20 (03) ◽  
pp. 557-564
Author(s):  
G. R. SAVICH ◽  
J. R. PEDRAZZANI ◽  
S. MAIMON ◽  
G. W. WICKS
Keyword(s):  
Leakage Current ◽  
Surface Passivation ◽  
Leakage Currents ◽  
Type Region ◽  
Surface Leakage Current ◽  
Unipolar Barrier ◽  
Trap Assisted Tunneling ◽  
Assisted Tunneling ◽  
Tunneling Currents ◽  
Surface Leakage

Tunneling currents and surface leakage currents are both contributors to the overall dark current which limits many semiconductor devices. Surface leakage current is generally controlled by applying a post-epitaxial passivation layer; however, surface passivation is often expensive and ineffective. Band-to-band and trap assisted tunneling currents cannot be controlled through surface passivants, thus an alternative means of control is necessary. Unipolar barriers, when appropriately applied to standard electronic device structures, can reduce the effects of both surface leakage and tunneling currents more easily and cost effectively than other methods, including surface passivation. Unipolar barriers are applied to the p -type region of a conventional, MBE grown, InAs based pn junction structures resulting in a reduction of surface leakage current. Placing the unipolar barrier in the n -type region of the device, has the added benefit of reducing trap assisted tunneling current as well as surface leakage currents. Conventional, InAs pn junctions are shown to exhibit surface leakage current while unipolar barrier photodiodes show no detectable surface currents.

Erratum: Study of gamma-ray emission by proton beam interaction with injected Boron atoms for future medical imaging applications

2017 ◽  
Vol 12 (04) ◽  
pp. E04001-E04001
Author(s):  
G Petringa ◽  
G.A.P Cirrone ◽  
C Caliri ◽  
G Cuttone ◽  
L Giuffrida ◽  
...  
Keyword(s):  
Medical Imaging ◽  
Proton Beam ◽  
Gamma Ray ◽  
Beam Interaction ◽  
Gamma Ray Emission

scholarly journals Surface Passivation of Boron Emitters on n-Type Silicon Solar Cells

2019 ◽  
Vol 11 (14) ◽  
pp. 3784
Author(s):  
Ji Yeon Hyun ◽  
Soohyun Bae ◽  
Yoon Chung Nam ◽  
Dongkyun Kang ◽  
Sang-Won Lee ◽  
...  
Keyword(s):  
Solar Cells ◽  
Surface Passivation ◽  
Atom Probe ◽  
Silicon Solar Cells ◽  
Capacitance Voltage ◽  
Passivation Layers ◽  
Chemical Passivation ◽  
Electron Energy Loss ◽  
Hydrogenation Effect ◽  
Antireflective Properties

Al2O3/SiNx stack passivation layers are among the most popular layers used for commercial silicon solar cells. In particular, aluminum oxide has a high negative charge, while the SiNx film is known to supply hydrogen as well as impart antireflective properties. Although there are many experimental results that show that the passivation characteristics are lowered by using the stack passivation layer, the cause of the passivation is not yet understood. In this study, we investigated the passivation characteristics of Al2O3/SiNx stack layers. To identify the hydrogenation effect, we analyzed the hydrogen migration with atom probe tomography by comparing the pre-annealing and post-annealing treatments. For chemical passivation, capacitance-voltage measurements were used to confirm the negative fixed charge density due to heat treatment. Moreover, the field-effect passivation was understood by confirming changes in the Al2O3 structure using electron energy-loss spectroscopy.

Effect of surface passivation on breakdown voltages of 4H-SiC Schottky barrier diodes

2017 ◽  
Vol 71 (10) ◽  
pp. 707-710 ◽  
Author(s):  
In Ho Kang ◽  
Moon Kyong Na ◽  
Ogyun Seok ◽  
Jeong Hyun Moon ◽  
H. W. Kim ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Surface Passivation ◽  
Schottky Barrier Diodes ◽  
Effect Of Surface

The Fabrication of Mercuric Iodide Detectors for Use in Wavelength Dispersive X-Ray Analysers and Backscatter Photon Measurements

1982 ◽  
Vol 16 ◽  
Author(s):  
John H. Howes ◽  
John Watling
Keyword(s):  
Room Temperature ◽  
Gamma Ray ◽  
Surface Passivation ◽  
Electrical Contact ◽  
Scintillation Counter ◽  
Radiation Detectors ◽  
Nuclear Radiation ◽  
Gamma Ray Spectrometry ◽  
Mercuric Iodide ◽  
X Ray

ABSTRACTThis paper describes the fabrication of mercuric iodide nuclear radiation detectors suitable for X and gamma ray spectrometry at room temperature. The active area of the detectors studied are between 0.2 and 1.5cm sq and they are up to 0.5mm thick. The method of producing a stable electrical contact to the crystal using sputtered germanium has been studied. The X-ray resolution of a 1.5cm sq. area detector at 32 keV is 2.3 keV FWHM when operated at room temperature in conjunction with a time variant filter amplifier. A factor which is important in the fabrication of the detector is the surface passivation necessary to achieve a useful detector life.This type of detector has been used on a wavelength dispersive X-ray spectrometer for energy measurements between 10 and 100 keV. The advantages over the scintillation counter, more commonly used, is the improved resolution of the HgI2 detector and its smaller size. The analyser is primarily used for the detection of low levels of heavy metals on particulate filters. The detectors have also been used on an experimental basis for gamma ray backscatter measurements in the medical field.

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