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Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts. / Omar A Al-Hartomy

Swansea University Author: Omar A Al-Hartomy

Abstract

Ballistic electron emission microscopy and spectroscopy (BEEM/BEES) have been employed by developing a basic desktop STM in air in order to study Ni-SiC samples. The electronic properties of Ni contacts to SiC are highly dependent on their manufacturing process and this study generated suitably thin...

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Published: 2005
Institution: Swansea University
Degree level: Master of Philosophy
Degree name: M.Phil
URI: https://cronfa.swan.ac.uk/Record/cronfa42875
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spelling 2018-09-04T14:04:35.9340672 v2 42875 2018-08-02 Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts. aaed19bb14e30575ac7686acc283774d NULL Omar A Al-Hartomy Omar A Al-Hartomy true true 2018-08-02 Ballistic electron emission microscopy and spectroscopy (BEEM/BEES) have been employed by developing a basic desktop STM in air in order to study Ni-SiC samples. The electronic properties of Ni contacts to SiC are highly dependent on their manufacturing process and this study generated suitably thin contacts for BEEM measurements that were Schottky in nature and made under UHV evaporation conditions. The sample also required an Ohmic contact to allow the detection of the BEEM current and these were formed using an Edwards evaporator. BEEM is a three terminal measurement based upon the generation of pico amp currents and as a result amplifier circuits with I/V conversion were used to amplify the BEEM current to give a voltage in the range of ±10V for input into an auxiliary channel of the basic STM control unit. Also, a sample holder (110 mm x 210 mm) was modified which allowed a 3rd contact to the sample within the usual STM set-up.During this work, simultaneous STM and BEEM images have been recorded at various tunnelling currents and bias voltages. These images show distinct differences and the interface behaviour appears modified by varying electrical properties between the Ni and SiC which are resolved spatially on the nanoscale within the BEEM image. Furthermore, measurements were made to determine the Schottky barrier height values using BEES in different locations by observing the ballistic current as a function of voltage. It was found that the Schottky barrier varied between 1.48 eV to 2.35 eVdepending on the region or features analysed. The interaction at room temperature between Ni and SiC is discussed in light of these measurements and compared to current literature to resolve the origin of the observed Schottky barrier height variations. E-Thesis Microscopy, spectroscopy 31 12 2005 2005-12-31 COLLEGE NANME Physics COLLEGE CODE Swansea University Master of Philosophy M.Phil 2018-09-04T14:04:35.9340672 2018-08-02T16:24:30.6794019 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Physics Omar A Al-Hartomy NULL 1 0042875-02082018162528.pdf 10821265.pdf 2018-08-02T16:25:28.7130000 Output 6574841 application/pdf E-Thesis true 2018-08-02T16:25:28.7130000 false
title Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts.
spellingShingle Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts.
Omar A Al-Hartomy
title_short Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts.
title_full Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts.
title_fullStr Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts.
title_full_unstemmed Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts.
title_sort Development of a desktop STM using ballistic electron emission microscopy and spectroscopy to study Ni-SiC Schottky contacts.
author_id_str_mv aaed19bb14e30575ac7686acc283774d
author_id_fullname_str_mv aaed19bb14e30575ac7686acc283774d_***_Omar A Al-Hartomy
author Omar A Al-Hartomy
author2 Omar A Al-Hartomy
format E-Thesis
publishDate 2005
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Physics{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Physics
document_store_str 1
active_str 0
description Ballistic electron emission microscopy and spectroscopy (BEEM/BEES) have been employed by developing a basic desktop STM in air in order to study Ni-SiC samples. The electronic properties of Ni contacts to SiC are highly dependent on their manufacturing process and this study generated suitably thin contacts for BEEM measurements that were Schottky in nature and made under UHV evaporation conditions. The sample also required an Ohmic contact to allow the detection of the BEEM current and these were formed using an Edwards evaporator. BEEM is a three terminal measurement based upon the generation of pico amp currents and as a result amplifier circuits with I/V conversion were used to amplify the BEEM current to give a voltage in the range of ±10V for input into an auxiliary channel of the basic STM control unit. Also, a sample holder (110 mm x 210 mm) was modified which allowed a 3rd contact to the sample within the usual STM set-up.During this work, simultaneous STM and BEEM images have been recorded at various tunnelling currents and bias voltages. These images show distinct differences and the interface behaviour appears modified by varying electrical properties between the Ni and SiC which are resolved spatially on the nanoscale within the BEEM image. Furthermore, measurements were made to determine the Schottky barrier height values using BEES in different locations by observing the ballistic current as a function of voltage. It was found that the Schottky barrier varied between 1.48 eV to 2.35 eVdepending on the region or features analysed. The interaction at room temperature between Ni and SiC is discussed in light of these measurements and compared to current literature to resolve the origin of the observed Schottky barrier height variations.
published_date 2005-12-31T03:53:49Z
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score 11.012678

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