Amorphous Semiconductor Analysis using Ion Beam Tools
EMSL Project ID
19197
Abstract
The goal of this proposal is to develop new materials for high resolution, room temperature gamma radiation detection. We propose to develop high Z, high resistivity, amorphous, semiconductors to be used as solid-state detectors at near ambient temperatures analogous to single crystal semi-conducting detectors (e.g. Ge or CdZnTe). Compared to single crystals, amorphous semiconductors have the advantages of rapid, cost effective, bulk fabrication, compositional flexibility, and greater electronic property control through composition. EMSL has a particle accelerator that can be used to quantitatively characterize in situ the radiation response of materials exposed to a flux of charged particles. The development and maturation of nuclear microprobes such as this has been one of the outstanding achievements in physics over the last few years. We intend to develop ion-beam methods to screen material combinations in a systematic and efficient manner. EMSL has expertise in materials characterization at its ion-beam characterization facility that can be used for thin-film compositional and transport characterization. These techniques include the use of Rutherford backscattering (RBS), elastic recoil detection analysis (ERDA), nuclear reaction analysis (NRA), and proton induced x-ray emission (PIXE) for compositional information with ppm accuracy for most elements from B (atomic number 5) on up. The particle accelerator can generate energetic beams of particles (p, He, Li, etc.) of several MeV that can be rastered across a specimen to perform a variety of measurements, including composition with part-per-million (ppm) accuracy, transport properties, device efficiency, and trap spectroscopy. WE intend to explore the development of ion beam induced current (IBIC) and scanning ion deep level transient spectroscopy (SIDLTS) as two techniques that are now widely used to characterize solar cells, integrated circuit materials, and, to some extent, radiation detectors. Together with current detectors, specimen imaging is possible to reveal regions of poor transport or defect trapping sites. Total device efficiency is readily obtained in this manner, plus a deeper understanding of properties. These techniques can be applied to the discovery of new materials for radiation detection provided a suitable materials holder and methods can be developed for making electrical contacts to different regions of the graded deposits. In conjunction with ion-beam methods, we will make use of standard photoluminescence measurements, high-resolution transmission electron microscopy (HRTEM), and laser Raman spectroscopy to fully characterize these materials.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-07-21
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
B. R. Johnson, B. J. Riley, S. K. Sundaram, J. V. Crum, C. Henager, Y. Zhang, V. Shuthanandan, C. E. Seifert, R. M. V. Ginhoven, C. Champberlain, A. Rockett, D. Hebert, andA. Aquino, "Synthesis and Characterization of Bulk Vitreous Cadmium Germanium Arsenide," Journal of the American Ceramic Society, 92[6] 1236-1243.2009.
Conference Presentation.
Amorphous Semiconductors for Gamma Radiation and Detection: Synthesis and Characterization. PNNL-SA-52405
Submitted and in review at a special conference issue of the IEEE Transactions on Nuclear Science (TNS), 2008.
Presented at SORMA West 2008, Berkeley, CA
Submitted and in review at Journal of the American Ceramics Society, 2008