Physical-Chemical Considerations for Semiconductor Room-Temperature Radiation Detectors

1993 ◽  
Vol 302 ◽  
Author(s):  
M. Schieber ◽  
H. Hermon ◽  
M. Roth
Keyword(s):  
Room Temperature ◽  
Gamma Ray ◽  
Energy Levels ◽  
Life Time ◽  
Radiation Detectors ◽  
Device Fabrication ◽  
Structural Defects ◽  
Physical Chemical ◽  
Temperature Operating ◽  
Temperature Radiation

ABSTRACTPhysical properties of large band gap semiconductors such as: HgI2, CdTe, Cd0.8Zn0.2Te, CdSe, Cd0.7Zn0.3Se, GaAs, PbI2 and TlBr are briefly reviewed and discussed in terms of their use as room temperature operating x-ray and gamma ray radiation detectors. It is shown that HgI2 which has the largest drift length for holes, λ=μτE i.e., the product of the mobility μh, life time τh and the electrical field E, is at present the leading material, being followed by the newly developed Cd0.8Zn0.2Te. Chemical defects in HgI2 were enhanced by doping the material with aliphatic, aromatic and oxyhydrocarbons as well as with excess Hg and I2 and the increase in unit cell parameter was studied as a function of the amount of dopant. The value of τ was measured as a function of dopant concentration and it was found that Hg doping causes the most severe trapping defects. Low temperature studies of τh down to 170K allowed the identification of the trapping energy levels and concentration of electrically active defects. Shallow traps of 0.13-0.18 eV stemming from deviation from stoichiometry of H-gI2 were found to be in the ppm level whereas deeper traps of 0.4-0.5 eV stemming from hydrocarbons were found to be in the ppb level. It is concluded that only extensive research on the physical, chemical and structural defects correlated with improved crystal growth and device fabrication methods, would lead, in the future, to improvements in λh also of the other large Eg semiconductor detector materials.

Mapping Detector Response Over the Area of a CdZnTe-Multiple-Electrode Detector

1997 ◽  
Vol 484 ◽  
Author(s):  
C. L. Lingren ◽  
B. Apotovsky ◽  
J. F. Butler ◽  
F. P. Doty ◽  
S. J. Friesenhahn ◽  
...  
Keyword(s):  
Electric Field ◽  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detectors ◽  
Uniform Electric Field ◽  
Detector Response ◽  
Hole Trapping ◽  
Temperature Radiation ◽  
Multiple Electrode

AbstractSemiconductor multiple-electrode detectors have been developed for the purpose of reducing effects of hole trapping in room-temperature radiation detectors.1,2 Some reported geometries maintain a nearly-uniform electric field inside the detector, but others generate an electric field that is very non-uniform and highly-concentrated at the anode. This paper reports the results of mapping such a detector (having a non-uniform electric field) with a finely collimated gamma-ray beam to determine the detector response as a function of position.

scholarly journals Study on In-Doped CdMgTe Crystals Grown by a Modified Vertical Bridgman Method Using the ACRT Technique

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4236 ◽  
Author(s):  
Pengfei Yu ◽  
Biru Jiang ◽  
Yongren Chen ◽  
Jiahong Zheng ◽  
Lijun Luan
Keyword(s):  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detectors ◽  
Bridgman Method ◽  
Second Phase ◽  
Zinc Blende ◽  
Te Inclusions ◽  
Vertical Bridgman ◽  
Temperature Radiation ◽  
Zinc Blende Structure

Cadmium–magnesium–telluride (CdMgTe) crystal was regarded as a potential semiconductor material. In this paper, an indium-doped Cd0.95Mg0.05Te ingot with 30 mm diameter and 120 mm length grown by a modified Bridgman method with excess Te condition was developed for room temperature gamma-ray detection. Characterizations revealed that the as-grown Cd0.95Mg0.05Te crystals had a cubic zinc-blende structure and additionally Te-rich second phase existed in the crystals. From the tip to tail of the ingot, the density of Te inclusions was about 103–105 cm−2. The crystals had a suitable band-gap range from 1.52–1.54 eV. Both infrared (IR) transmittance and resistivity were relatively low. Photoluminescence measurement indicated that the ingot had more defects. Fortunately, after annealing, IR transmittance and the resistivity were significantly enhanced due to the elimination of Te inclusions. CdMgTe crystal after annealing showed a good crystal quality. The energy resolutions of the detector for 241Am and 137Cs gamma-ray were 12.7% and 8.6%, respectively. The mobility-lifetime product for electron was 1.66 × 10−3 cm2/V. Thus, this material could be used for room temperature radiation detectors.

Mapping Detector Response Over the Area of a CdZnTe-Multiple-Electrode Detector

1997 ◽  
Vol 487 ◽  
Author(s):  
C. L. Lingren ◽  
B. Apotovsky ◽  
J. F. Butler ◽  
F. P. Doty ◽  
S. J. Friesenhahn ◽  
...  
Keyword(s):  
Electric Field ◽  
Room Temperature ◽  
Gamma Ray ◽  
Radiation Detectors ◽  
Uniform Electric Field ◽  
Detector Response ◽  
Hole Trapping ◽  
Temperature Radiation ◽  
Multiple Electrode

AbstractSemiconductor multiple-electrode detectors have been developed for the purpose of reducing effects of hole trapping in room-temperature radiation detectors. Some reported geometries maintain a nearly-uniform electric field inside the detector, but others generate an electric field that is very non-uniform and highly-concentrated at the anode. This paper reports the results of mapping such a detector (having a non-uniform electric field) with a finely collimated gamma-ray beam to determine the detector response as a function of position.

High quality planar Cd1-xMnxTe room-temperature radiation detectors

2021 ◽  
Vol 119 (6) ◽  
pp. 062103
Author(s):  
A. Brovko ◽  
P. Rusian ◽  
L. Chernyak ◽  
A. Ruzin
Keyword(s):  
Room Temperature ◽  
Radiation Detectors ◽  
High Quality ◽  
Temperature Radiation

scholarly journals Pulse-shape analysis in Cd0.9Zn0.1Te0.98Se0.02 room-temperature radiation detectors

2020 ◽  
Vol 116 (16) ◽  
pp. 162107 ◽  
Author(s):  
Sandeep K. Chaudhuri ◽  
Mohsin Sajjad ◽  
Krishna C. Mandal
Keyword(s):  
Shape Analysis ◽  
Pulse Shape ◽  
Room Temperature ◽  
Radiation Detectors ◽  
Pulse Shape Analysis ◽  
Temperature Radiation

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.

Process Monitoring for Fabrication of Mercuric Iodide Room Temperature Radiation Detectors

1993 ◽  
Vol 324 ◽  
Author(s):  
J. M. Van Scyoc ◽  
T. E. Schlesinger ◽  
H. Yao ◽  
R. B. James ◽  
M. Natarajan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Radiation Detectors ◽  
Electrical Contacts ◽  
Careful Study ◽  
Mercuric Iodide ◽  
Optical Functions ◽  
Processing Step ◽  
Material Choice ◽  
Temperature Radiation ◽  
Processing Steps

AbstractIn the fabrication of mercuric iodide room temperature radiation detectors, as in any semiconductor process, the quality of the final device can be very sensitive to the details of the processing steps. Each processing step can either reduce the intrinsic defects and those extrinsic defects introduced by earlier steps, or it can introduce new defects. In mercuric iodide these defects can act as trapping and recombination centers, thereby degrading immediate device performance or leading to long-term reliability problems. With careful study and monitoring of each step, the process can be modified to improve the end product. In this work we used several techniques to study processing steps and their effects. Photoluminescence spectroscopy and photoionization revealed defects introduced during processing. One critical step is the formation of electrical contacts, as both the material choice and deposition method have an impact. Four point probe sheet resistance methods were used to characterize the loss of material from the contact as it reacted with or moved into the bulk semiconductor. Ellipsometry was used to characterize the intrinsic optical functions of the material, and to study the effects of surface aging on these functions. Results from this work provide suggestions for the modification and monitoring of the detector fabrication process.

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