{"id":{"repo_id":"vcu","oai_identifier":"oai:scholarscompass.vcu.edu:etd-2245"},"canonical_url":"https://search.dev.ndltd.org/etd/vcu/oai:scholarscompass.vcu.edu:etd-2245","repository":{"repo_id":"vcu","name":"Virginia Commonwealth University","base_url":"https://scholarscompass.vcu.edu/do/oai/"},"display":{"title":"AFM and C-AFM Studies of GaN Films","abstract":"This thesis uses the techniques of atomic force microscope (AFM) and conductive AFM (C-AFM) to study the conduction properties of n-type GaN films. A total of 16 samples were examined and grouped according to their surface morphologies and conduction behaviors. The most common type of surface morpliology was that of Ga-rich samples having undulating \"hillocks\" with interspersed holes. Although most of the samples had this common morphology, their local conduction behaviors were not all similar. Local I-V spectra of the tip-sample Schottky contact could be grouped according to three major types: low leakage, high leakage, and \"p-type\". The highest quality samples with low leakage were usually grown at moderate temperatures (~650°C). For such samples, localized leakage only occurred at screw dislocations located at small pits terminating surface hillocks. I-V spectra taken on and off such hillocks were fit in forward bias to determine whether field emission or Frenkel-Poole conduction were dominant. Although field emission is a good fit compared to Frenkel-Poole, yielding reasonable values for the barrier height, the results are not yet conclusive without variable temperature studies.","abstract_html":"This thesis uses the techniques of atomic force microscope (AFM) and conductive AFM (C-AFM) to study the conduction properties of n-type GaN films. A total of 16 samples were examined and grouped according to their surface morphologies and conduction behaviors. The most common type of surface morpliology was that of Ga-rich samples having undulating "hillocks" with interspersed holes. Although most of the samples had this common morphology, their local conduction behaviors were not all similar. Local I-V spectra of the tip-sample Schottky contact could be grouped according to three major types: low leakage, high leakage, and "p-type". The highest quality samples with low leakage were usually grown at moderate temperatures (~650°C). For such samples, localized leakage only occurred at screw dislocations located at small pits terminating surface hillocks. I-V spectra taken on and off such hillocks were fit in forward bias to determine whether field emission or Frenkel-Poole conduction were dominant. Although field emission is a good fit compared to Frenkel-Poole, yielding reasonable values for the barrier height, the results are not yet conclusive without variable temperature studies.","abstract_has_math":false,"creators":["Cooper, Katherine"],"institution":null,"degree_name":"Master of Science","degree_level":"Thesis","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Dr. Alison Baski"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2005,"date_issued":"2005-01-01T08:00:00Z","date_published":"2005-01-01T08:00:00Z","updated_at":"2026-07-24T05:55:08Z","subjects":["spectra","GaN films","AFM","Physical Sciences and Mathematics","Physics"],"languages":[],"rights":["© The Author"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarscompass.vcu.edu/etd/1246"],"render_values":[{"text":"https://scholarscompass.vcu.edu/etd/1246","href":"https://scholarscompass.vcu.edu/etd/1246","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.25772/BBH7-DV70","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dr. Alison Baski"]},{"key":"dc:creator","label":"Author","values":["Cooper, Katherine"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2014-07-09T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["spectra","GaN films","AFM","Physical Sciences and Mathematics","Physics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["© The Author"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://doi.org/10.25772/BBH7-DV70","https://scholarscompass.vcu.edu/etd/1246"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis uses the techniques of atomic force microscope (AFM) and conductive AFM (C-AFM) to study the conduction properties of n-type GaN films. A total of 16 samples were examined and grouped according to their surface morphologies and conduction behaviors. The most common type of surface morpliology was that of Ga-rich samples having undulating \"hillocks\" with interspersed holes. Although most of the samples had this common morphology, their local conduction behaviors were not all similar. Local I-V spectra of the tip-sample Schottky contact could be grouped according to three major types: low leakage, high leakage, and \"p-type\". The highest quality samples with low leakage were usually grown at moderate temperatures (~650°C). For such samples, localized leakage only occurred at screw dislocations located at small pits terminating surface hillocks. I-V spectra taken on and off such hillocks were fit in forward bias to determine whether field emission or Frenkel-Poole conduction were dominant. Although field emission is a good fit compared to Frenkel-Poole, yielding reasonable values for the barrier height, the results are not yet conclusive without variable temperature studies."]},{"key":"dc:title","label":"Title","values":["AFM and C-AFM Studies of GaN Films"]}]}],"canonical_facts":{"dc:contributor":["Dr. Alison Baski"],"dc:creator":["Cooper, Katherine"],"dc:date.available":["2014-07-09T07:00:00Z"],"dc:description.abstract":["This thesis uses the techniques of atomic force microscope (AFM) and conductive AFM (C-AFM) to study the conduction properties of n-type GaN films. A total of 16 samples were examined and grouped according to their surface morphologies and conduction behaviors. The most common type of surface morpliology was that of Ga-rich samples having undulating \"hillocks\" with interspersed holes. Although most of the samples had this common morphology, their local conduction behaviors were not all similar. Local I-V spectra of the tip-sample Schottky contact could be grouped according to three major types: low leakage, high leakage, and \"p-type\". The highest quality samples with low leakage were usually grown at moderate temperatures (~650°C). For such samples, localized leakage only occurred at screw dislocations located at small pits terminating surface hillocks. I-V spectra taken on and off such hillocks were fit in forward bias to determine whether field emission or Frenkel-Poole conduction were dominant. Although field emission is a good fit compared to Frenkel-Poole, yielding reasonable values for the barrier height, the results are not yet conclusive without variable temperature studies."],"dc:identifier":["https://doi.org/10.25772/BBH7-DV70","https://scholarscompass.vcu.edu/etd/1246"],"dc:rights":["© The Author"],"dc:subject":["spectra","GaN films","AFM","Physical Sciences and Mathematics","Physics"],"dc:title":["AFM and C-AFM Studies of GaN Films"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science"]},"updated_at":"2026-07-24T05:55:08Z"}