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Title: Effect of chlorination on the TlBr band edges for improved room temperature radiation detectors: Effect of chlorination on the TlBr band edges for radiation detectors

Abstract

Thallium bromide (TlBr) crystals subjected to hydrochloric acid (HCl) chemical treatments have been shown to advantageously affect device performance and longevity in TlBr-based room temperature radiation detectors, yet the exact mechanisms of the improvements remain poorly understood. Here in this paper, we investigate the influence of several HCl chemical treatments on device-grade TlBr and describe the changes in the composition and electronic structure of the surface. Composition analysis and depth profiles obtained from secondary ion mass spectrometry (SIMS) identify the extent to which each HCl etch condition affects the detector surface region and forms of a graded TlBr/TlBr 1-xCL x surface heterojunction. Using a combination of X-ray photoemission spectroscopy (XPS) and hybrid density functional calculations, we are able to determine the valence band offsets, band gaps, and conduction band offsets as a function of Cl content over the entire composition range of TIBr 1-xC1 X. This study establishes a strong correlation between device process conditions, surface chemistry, and electronic structure with the goal of further optimizing the long-term stability and radiation response of TlBr-based detectors.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1418904
Report Number(s):
LLNL-JRNL-661938
Journal ID: ISSN 0370-1972
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physica Status Solidi B. Basic Solid State Physics
Additional Journal Information:
Journal Volume: 252; Journal Issue: 6; Journal ID: ISSN 0370-1972
Publisher:
Wiley-Blackwell
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; density functional theory; radiation detector; surface treatment; thallium halide; X-ray photoemission spectroscopy

Citation Formats

Varley, J. B., Conway, A. M., Voss, L. F., Swanberg, E., Graff, R. T., Nikolic, R. J., Payne, S. A., Lordi, V., and Nelson, A. J. Effect of chlorination on the TlBr band edges for improved room temperature radiation detectors: Effect of chlorination on the TlBr band edges for radiation detectors. United States: N. p., 2015. Web. doi:10.1002/pssb.201451662.
Varley, J. B., Conway, A. M., Voss, L. F., Swanberg, E., Graff, R. T., Nikolic, R. J., Payne, S. A., Lordi, V., & Nelson, A. J. Effect of chlorination on the TlBr band edges for improved room temperature radiation detectors: Effect of chlorination on the TlBr band edges for radiation detectors. United States. doi:10.1002/pssb.201451662.
Varley, J. B., Conway, A. M., Voss, L. F., Swanberg, E., Graff, R. T., Nikolic, R. J., Payne, S. A., Lordi, V., and Nelson, A. J. Mon . "Effect of chlorination on the TlBr band edges for improved room temperature radiation detectors: Effect of chlorination on the TlBr band edges for radiation detectors". United States. doi:10.1002/pssb.201451662. https://www.osti.gov/servlets/purl/1418904.
@article{osti_1418904,
title = {Effect of chlorination on the TlBr band edges for improved room temperature radiation detectors: Effect of chlorination on the TlBr band edges for radiation detectors},
author = {Varley, J. B. and Conway, A. M. and Voss, L. F. and Swanberg, E. and Graff, R. T. and Nikolic, R. J. and Payne, S. A. and Lordi, V. and Nelson, A. J.},
abstractNote = {Thallium bromide (TlBr) crystals subjected to hydrochloric acid (HCl) chemical treatments have been shown to advantageously affect device performance and longevity in TlBr-based room temperature radiation detectors, yet the exact mechanisms of the improvements remain poorly understood. Here in this paper, we investigate the influence of several HCl chemical treatments on device-grade TlBr and describe the changes in the composition and electronic structure of the surface. Composition analysis and depth profiles obtained from secondary ion mass spectrometry (SIMS) identify the extent to which each HCl etch condition affects the detector surface region and forms of a graded TlBr/TlBr1-xCLx surface heterojunction. Using a combination of X-ray photoemission spectroscopy (XPS) and hybrid density functional calculations, we are able to determine the valence band offsets, band gaps, and conduction band offsets as a function of Cl content over the entire composition range of TIBr1-xC1X. This study establishes a strong correlation between device process conditions, surface chemistry, and electronic structure with the goal of further optimizing the long-term stability and radiation response of TlBr-based detectors.},
doi = {10.1002/pssb.201451662},
journal = {Physica Status Solidi B. Basic Solid State Physics},
number = 6,
volume = 252,
place = {United States},
year = {Mon Feb 09 00:00:00 EST 2015},
month = {Mon Feb 09 00:00:00 EST 2015}
}

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