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Title: Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors

Abstract

Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current or leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.

Authors:
 [1]
  1. California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
990413
Report Number(s):
LLNL-TH-425864
TRN: US1007374
DOE Contract Number:  
W-7405-ENG-48; AC52-07NA27344
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 42 ENGINEERING; 22 GENERAL STUDIES OF NUCLEAR REACTORS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ARGON IONS; ASTRONOMY; ATOMIC NUMBER; CADMIUM TELLURIDES; DEPOSITION; DESIGN; FIELD EMISSION; LEAKAGE CURRENT; MEDICINE; NATIONAL SECURITY; PERFORMANCE; SEMICONDUCTOR MATERIALS; SIMULATION; SIMULATORS; THERMIONIC EMISSION; THERMIONICS

Citation Formats

Beck, Patrick R. Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors. United States: N. p., 2010. Web. doi:10.2172/990413.
Beck, Patrick R. Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors. United States. doi:10.2172/990413.
Beck, Patrick R. Thu . "Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors". United States. doi:10.2172/990413. https://www.osti.gov/servlets/purl/990413.
@article{osti_990413,
title = {Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors},
author = {Beck, Patrick R.},
abstractNote = {Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current or leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.},
doi = {10.2172/990413},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2010},
month = {1}
}

Thesis/Dissertation:
Other availability
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