FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)
Abstract
We describe progress in the development of new materials for portable, room-temperature, gamma-radiation detection at Pacific Northwest National Laboratory at the Hanford Site in Washington State. High Z, high resistivity, amorphous semiconductors are being designed for use as solid-state detectors at near ambient temperatures; principles of operation are analogous to single-crystal semiconducting detectors. Amorphous semiconductors have both advantages and disadvantages compared to single crystals, and this project is developing methods to mitigate technical problems and design optimized material for gamma detection. Several issues involved in the fabrication of amorphous semiconductors are described, including reaction thermodynamics and kinetics, the development of pyrolytic coating, and the synthesis of ingots. The characterization of amorphous semiconductors is described, including sectioning and polishing protocols, optical microscopy, X-ray diffraction, scanning electron microscopy, optical spectroscopy, particle-induced X-ram emission, Rutherford backscattering, and electrical testing. Then collaboration with the University of Illinois at Urbana-Champaign is discussed in the areas of Hall-effect measurements and current voltage data. Finally, we discuss the strategy for continuing the program.
- Authors:
- Publication Date:
- Research Org.:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1047430
- Report Number(s):
- PNNL-16429
19197; NN2001000; TRN: US201216%%395
- DOE Contract Number:
- AC05-76RL01830
- Resource Type:
- Technical Report
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; AMBIENT TEMPERATURE; BACKSCATTERING; DESIGN; DETECTION; ELECTRICAL TESTING; FABRICATION; GAMMA DETECTION; GAMMA RADIATION; HALL EFFECT; KINETICS; MONOCRYSTALS; OPTICAL MICROSCOPY; POLISHING; SCANNING ELECTRON MICROSCOPY; SPECTROSCOPY; SYNTHESIS; THERMODYNAMICS; X-RAY DIFFRACTION; gamma radiation detection; amorphous semiconductors; Environmental Molecular Sciences Laboratory
Citation Formats
Johnson, Bradley R., Riley, Brian J., Crum, Jarrod V., Sundaram, S. K., Henager, Charles H., Zhang, Yanwen, and Shutthanandan, V. FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD). United States: N. p., 2007.
Web. doi:10.2172/1047430.
Johnson, Bradley R., Riley, Brian J., Crum, Jarrod V., Sundaram, S. K., Henager, Charles H., Zhang, Yanwen, & Shutthanandan, V. FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD). United States. doi:10.2172/1047430.
Johnson, Bradley R., Riley, Brian J., Crum, Jarrod V., Sundaram, S. K., Henager, Charles H., Zhang, Yanwen, and Shutthanandan, V. Mon .
"FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)". United States.
doi:10.2172/1047430. https://www.osti.gov/servlets/purl/1047430.
@article{osti_1047430,
title = {FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)},
author = {Johnson, Bradley R. and Riley, Brian J. and Crum, Jarrod V. and Sundaram, S. K. and Henager, Charles H. and Zhang, Yanwen and Shutthanandan, V.},
abstractNote = {We describe progress in the development of new materials for portable, room-temperature, gamma-radiation detection at Pacific Northwest National Laboratory at the Hanford Site in Washington State. High Z, high resistivity, amorphous semiconductors are being designed for use as solid-state detectors at near ambient temperatures; principles of operation are analogous to single-crystal semiconducting detectors. Amorphous semiconductors have both advantages and disadvantages compared to single crystals, and this project is developing methods to mitigate technical problems and design optimized material for gamma detection. Several issues involved in the fabrication of amorphous semiconductors are described, including reaction thermodynamics and kinetics, the development of pyrolytic coating, and the synthesis of ingots. The characterization of amorphous semiconductors is described, including sectioning and polishing protocols, optical microscopy, X-ray diffraction, scanning electron microscopy, optical spectroscopy, particle-induced X-ram emission, Rutherford backscattering, and electrical testing. Then collaboration with the University of Illinois at Urbana-Champaign is discussed in the areas of Hall-effect measurements and current voltage data. Finally, we discuss the strategy for continuing the program.},
doi = {10.2172/1047430},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
-
The general purpose of this work has been to clarify the steady-state photoelectronic properties of amorphous hydrogenated silicon and related semiconductors, and to contribute to understanding the underlying electronic band structure. The first phase of this work concentrated on transient phototransport measured on samples of doped and undoped a-Si:H. In the second year of this contract, we have concentrated on the examination of the possibility of investigating the doping of a-Si:H by P through neutron transmutation doping, examination of the theory of photoluminescence, completion of a study on the effect of carrier loss to deep traps during dispersive transport, andmore »
-
Novel silane and disilane precursors to amorphous semiconductors. Annual report, 1 April 1985-31 March 1986
This report describes the preparation and characterization of amorphous fluorohydrogenated silicon thin films. The novel approach lies in the use of fluorinated silanes as film precursors. This method has the advantages of well-defined initial ratios of hydrogen and fluorine and a greatly reduced hazards in the handling of the gas. Fluorine derivatives of both silane and disilane were synthesized. A conventional method, glow discharge (or plasma-enhanced chemical vapor deposition), was employed to prepare amorphous silicon on glass and Si wafers. The electrical characterization of the material prepared from difluorosilane (the main precursor during the contract period covered in this report)more » -
Drift mobilities by time-of-flight methods and time-dependent phototransport in the nanosecond regime in amorphous semiconductors. Annual report, May 1, 1984-April 30, 1985
The purpose of this work is to elucidate transient phototransport and related phenomena in amorphous semiconductors, which have a bearing on the steady-state photoelectronic properties and the underlying electronic band structure. The approach has been to produce samples of a-Si:H and a-Si:H:F, to characterize them very well chemically, structurally and optically, and then to study the dispersive transport by the time-of-flight technique. This gives information on the mode of transport in these disordered substances. By studying the collected charge versus applied electric field on intrinsic and doped samples, one is also able to obtain information on the electron and holemore » -
Research on defects and transport in amorphous silicon-based semiconductors. Annual subcontract report, 20 February 1991--19 February 1992
This report describes the results from research on two topics: (1) the effects of light-soaking on the electron drift mobility in a-Si:H, and (2) modulated electron spin resonance measurements and their relationship to the electronic correlation energy of the D center in a-Si:H. Both of these projects were undertaken to better determine where the ``standard`` model for a-Si:H breaks down. The standard model is reasonably successful in accounting for the most elementary ``deep trapping`` aspects of electron and hole transport in a-Si:H, and it accounts adequately for the sub-band-gap optical properties. However, it is much less clear whether it providesmore » -
Small-angle x-ray scattering studies of microvoids in amorphous-silicon-based semiconductors. Annual subcontract report, February 1, 1992--January 31, 1993
Our general objectives are to provide new details of the microstructure for the size scale from about 1 to 30 nm in high-quality a-Si:H and related alloys prepared by current state-of-the-art deposition methods as well as by new and emerging deposition technologies and thereby help determine the role of microvoids and other density fluctuations in controlling the opto-electronic properties. More specifically, the objectives are to determine whether the presence of microstructure as detected by small-angle x-ray scattering (SAXS) (1) limits the photovoltaic properties of device-quality a-Si:H, (2) plays a role in determining the photo-stability of a-Si:H, and (3) is responsiblemore »