{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25623"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25623","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Scanning electron microscope technique for measuring electrical conductivity: Application to tetrathiafulvalene-tetracyanoquinodimethane","abstract":"A new technique for measuring the electrical conductivity of small samples and its application to the organic conductor tetrathiafulvalenetetracyanoquinodimethane (TTF-TCNQ) is reported. A movable current sour(:e provided by the electron beam of a scanning electron microscope is used to map out the potential distribution on crystal faces containing the a-b crystallographic axes. Silver paint contacts are used to return the beam current to ground and measure voltage changes as the beam position is moved. The results of the new technique are confirmed and complemented by the conventional movable contact method and the extension of both methods to low temperature is discussed. The potential distributions for our samples reveal frequently occurring irregularities in current flow which are attributable to sample imperfections and inhomogeneities in the silver paint contacts. Methods are presented whereby the commonly reported conductivities 0a and 0b can be determined despite the presence of certain current flow irregularities; room temperature values are found to be: 0b = 490 ±80 (ncm)-l and sigma-a = 1.21 ±.15 (Ohmcm)-l. The relationship of sigma-a and sigma-b to the elements of the correctly expressed conductivity tensor for TTF-TCNQ is clarified. The influence of contact inhomogeneities on four-probe measurements of the temperature dependence of the £-axis conductivity as determined with an electrolytic tank model are also presented. It is found that there is a large probability of slightly underestimating conductivity, but that it is possible in a small number of cases to greatly overestimate conductivity.","abstract_html":"A new technique for measuring the electrical conductivity of small samples and its application to the organic conductor tetrathiafulvalenetetracyanoquinodimethane (TTF-TCNQ) is reported. A movable current sour(:e provided by the electron beam of a scanning electron microscope is used to map out the potential distribution on crystal faces containing the a-b crystallographic axes. Silver paint contacts are used to return the beam current to ground and measure voltage changes as the beam position is moved. The results of the new technique are confirmed and complemented by the conventional movable contact method and the extension of both methods to low temperature is discussed. The potential distributions for our samples reveal frequently occurring irregularities in current flow which are attributable to sample imperfections and inhomogeneities in the silver paint contacts. Methods are presented whereby the commonly reported conductivities 0a and 0b can be determined despite the presence of certain current flow irregularities; room temperature values are found to be: 0b = 490 ±80 (ncm)-l and sigma-a = 1.21 ±.15 (Ohmcm)-l. The relationship of sigma-a and sigma-b to the elements of the correctly expressed conductivity tensor for TTF-TCNQ is clarified. The influence of contact inhomogeneities on four-probe measurements of the temperature dependence of the £-axis conductivity as determined with an electrolytic tank model are also presented. It is found that there is a large probability of slightly underestimating conductivity, but that it is possible in a small number of cases to greatly overestimate conductivity.","abstract_has_math":false,"creators":["Long, James Peter"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Slichter, C.P."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-07-01T17:40:21Z","date_published":"2011-07-01T17:40:21Z","updated_at":"2026-07-22T22:25:24Z","subjects":["tetracyanoquinodimethane (TTF-TCNQ)","Scanning electron microscopy (SEM)","electrical conductivity"],"languages":["en"],"rights":["1977 James Peter Long"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["252843"],"render_values":[{"text":"252843","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25623","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Slichter, C.P."]},{"key":"dc:creator","label":"Author","values":["Long, James Peter"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-07-01T17:40:21Z","10000-01-01","1977"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["tetracyanoquinodimethane (TTF-TCNQ)","Scanning electron microscopy (SEM)","electrical conductivity"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1977 James Peter Long"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["252843","http://hdl.handle.net/2142/25623"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["A new technique for measuring the electrical conductivity of small samples and its application to the organic conductor tetrathiafulvalenetetracyanoquinodimethane (TTF-TCNQ) is reported. A movable current sour(:e provided by the electron beam of a scanning electron microscope is used to map out the potential distribution on crystal faces containing the a-b crystallographic axes. Silver paint contacts are used to return the beam current to ground and measure voltage changes as the beam position is moved. The results of the new technique are confirmed and complemented by the conventional movable contact method and the extension of both methods to low temperature is discussed. The potential distributions for our samples reveal frequently occurring irregularities in current flow which are attributable to sample imperfections and inhomogeneities in the silver paint contacts. Methods are presented whereby the commonly reported conductivities 0a and 0b can be determined despite the presence of certain current flow irregularities; room temperature values are found to be: 0b = 490 ±80 (ncm)-l and sigma-a = 1.21 ±.15 (Ohmcm)-l. The relationship of sigma-a and sigma-b to the elements of the correctly expressed conductivity tensor for TTF-TCNQ is clarified. The influence of contact inhomogeneities on four-probe measurements of the temperature dependence of the £-axis conductivity as determined with an electrolytic tank model are also presented. It is found that there is a large probability of slightly underestimating conductivity, but that it is possible in a small number of cases to greatly overestimate conductivity.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-01T17:40:21Z No. of bitstreams: 1 1977_long.pdf: 7201819 bytes, checksum: 85f637f0c2d84ab616893b046f5abd74 (MD5)","Made available in DSpace on 2011-07-01T17:40:21Z (GMT). No. of bitstreams: 1 1977_long.pdf: 7201819 bytes, checksum: 85f637f0c2d84ab616893b046f5abd74 (MD5) Previous issue date: 1977","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-01T17:40:21Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:32:33-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Scanning electron microscope technique for measuring electrical conductivity: Application to tetrathiafulvalene-tetracyanoquinodimethane"]}]}],"canonical_facts":{"dc:contributor":["Slichter, C.P."],"dc:creator":["Long, James Peter"],"dc:date":["2011-07-01T17:40:21Z","10000-01-01","1977"],"dc:description":["A new technique for measuring the electrical conductivity of small samples and its application to the organic conductor tetrathiafulvalenetetracyanoquinodimethane (TTF-TCNQ) is reported. A movable current sour(:e provided by the electron beam of a scanning electron microscope is used to map out the potential distribution on crystal faces containing the a-b crystallographic axes. Silver paint contacts are used to return the beam current to ground and measure voltage changes as the beam position is moved. The results of the new technique are confirmed and complemented by the conventional movable contact method and the extension of both methods to low temperature is discussed. The potential distributions for our samples reveal frequently occurring irregularities in current flow which are attributable to sample imperfections and inhomogeneities in the silver paint contacts. Methods are presented whereby the commonly reported conductivities 0a and 0b can be determined despite the presence of certain current flow irregularities; room temperature values are found to be: 0b = 490 ±80 (ncm)-l and sigma-a = 1.21 ±.15 (Ohmcm)-l. The relationship of sigma-a and sigma-b to the elements of the correctly expressed conductivity tensor for TTF-TCNQ is clarified. The influence of contact inhomogeneities on four-probe measurements of the temperature dependence of the £-axis conductivity as determined with an electrolytic tank model are also presented. It is found that there is a large probability of slightly underestimating conductivity, but that it is possible in a small number of cases to greatly overestimate conductivity.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-01T17:40:21Z No. of bitstreams: 1 1977_long.pdf: 7201819 bytes, checksum: 85f637f0c2d84ab616893b046f5abd74 (MD5)","Made available in DSpace on 2011-07-01T17:40:21Z (GMT). No. of bitstreams: 1 1977_long.pdf: 7201819 bytes, checksum: 85f637f0c2d84ab616893b046f5abd74 (MD5) Previous issue date: 1977","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-01T17:40:21Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:32:33-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["252843","http://hdl.handle.net/2142/25623"],"dc:language":["en"],"dc:rights":["1977 James Peter Long"],"dc:subject":["tetracyanoquinodimethane (TTF-TCNQ)","Scanning electron microscopy (SEM)","electrical conductivity"],"dc:title":["Scanning electron microscope technique for measuring electrical conductivity: Application to tetrathiafulvalene-tetracyanoquinodimethane"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:24Z"}