III-Nitride Membranes for Thermal Bio-Sensing and Solar Hydrogen Generation

Handle URI:
http://hdl.handle.net/10754/625485
Title:
III-Nitride Membranes for Thermal Bio-Sensing and Solar Hydrogen Generation
Authors:
Elafandy, Rami Tarek Mahmoud ( 0000-0002-8529-2967 )
Abstract:
III-nitride nanostructures have generated tremendous scientific and technological interests in studying and engineering their low dimensional physics phenomena. Among these, 2D planar, free standing III-nitride nanomembranes are unrivalled in their scalability for high yield manufacture and can be mechanically manipulated. Due to the increase in their surface to volume ratio and the manifestation of quantum phenomena, these nanomembranes acquire unique physical properties. Furthermore, III-nitride membranes are chemically stable and biocompatible. Finally, nanomembranes are highly flexible and can follow curvilinear surfaces present in biological systems. However, being free-standing, requires especially new techniques for handling nanometers or micrometers thick membrane devices. Furthermore, effectively transferring these membrane devices to other substrates is not a direct process which requires the use of photoresists, solvents and/or elastomers. Finally, as the membranes are transferred, they need to be properly attached for subsequent device fabrications, which often includes spin coating and rinsing steps. These engineering complications have impeded the development of novel devices based on III-nitride membranes. In this thesis, we demonstrate the versatility of III-nitride membranes where we develop a thermal bio-sensor nanomembrane and solar energy photo-anode membrane. First, we present a novel preparation technique of nanomembranes with new characteristics; having no threading dislocation cores. We then perform optical characterization to reveal changes in their defect densities compared to the bulk crystal. We also study their mechanical properties where we successfully modulate their bandgap emission by 55 meV through various external compressive and tensile strain fields. Furthermore, we characterize the effect of phonon-boundary scattering on their thermal properties where we report a reduction of thermal conductivity from 130 to 9 W/mK. We employ these modifications to develop a thermal biosensor, which conformally gets attached to cells to measure their thermal properties. We also assess the statistical significance of our measurements to differentiate between different cell lines based on their measured thermal properties. Finally, we demonstrate the application of nanomembranes in solar-based water-splitting by merging them with nanowires to form nanowire membranes which are used to fabricate membrane photo-anodes. Finally, through optical, chemical and electrochemical measurements, we demonstrate their superior operations compared to typical fabrication techniques.
Advisors:
Ooi, Boon S. ( 0000-0001-9606-5578 )
Committee Member:
Alshareef, Husam N. ( 0000-0001-5029-2142 ) ; Salama, Khaled N. ( 0000-0001-7742-1282 ) ; Merzaban, Jasmeen ( 0000-0002-7276-2907 ) ; Gan, Qiaoqiang
KAUST Department:
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Program:
Electrical Engineering
Issue Date:
Sep-2017
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorOoi, Boon S.en
dc.contributor.authorElafandy, Rami Tarek Mahmouden
dc.date.accessioned2017-09-21T04:48:59Z-
dc.date.available2017-09-21T04:48:59Z-
dc.date.issued2017-09-
dc.identifier.urihttp://hdl.handle.net/10754/625485-
dc.description.abstractIII-nitride nanostructures have generated tremendous scientific and technological interests in studying and engineering their low dimensional physics phenomena. Among these, 2D planar, free standing III-nitride nanomembranes are unrivalled in their scalability for high yield manufacture and can be mechanically manipulated. Due to the increase in their surface to volume ratio and the manifestation of quantum phenomena, these nanomembranes acquire unique physical properties. Furthermore, III-nitride membranes are chemically stable and biocompatible. Finally, nanomembranes are highly flexible and can follow curvilinear surfaces present in biological systems. However, being free-standing, requires especially new techniques for handling nanometers or micrometers thick membrane devices. Furthermore, effectively transferring these membrane devices to other substrates is not a direct process which requires the use of photoresists, solvents and/or elastomers. Finally, as the membranes are transferred, they need to be properly attached for subsequent device fabrications, which often includes spin coating and rinsing steps. These engineering complications have impeded the development of novel devices based on III-nitride membranes. In this thesis, we demonstrate the versatility of III-nitride membranes where we develop a thermal bio-sensor nanomembrane and solar energy photo-anode membrane. First, we present a novel preparation technique of nanomembranes with new characteristics; having no threading dislocation cores. We then perform optical characterization to reveal changes in their defect densities compared to the bulk crystal. We also study their mechanical properties where we successfully modulate their bandgap emission by 55 meV through various external compressive and tensile strain fields. Furthermore, we characterize the effect of phonon-boundary scattering on their thermal properties where we report a reduction of thermal conductivity from 130 to 9 W/mK. We employ these modifications to develop a thermal biosensor, which conformally gets attached to cells to measure their thermal properties. We also assess the statistical significance of our measurements to differentiate between different cell lines based on their measured thermal properties. Finally, we demonstrate the application of nanomembranes in solar-based water-splitting by merging them with nanowires to form nanowire membranes which are used to fabricate membrane photo-anodes. Finally, through optical, chemical and electrochemical measurements, we demonstrate their superior operations compared to typical fabrication techniques.en
dc.language.isoenen
dc.subjectGallium Nitradeen
dc.subjectNanomembraneen
dc.subjectBio-sensoren
dc.subjectWater Splittingen
dc.subjectThermal propertiesen
dc.subjectExfoliationen
dc.titleIII-Nitride Membranes for Thermal Bio-Sensing and Solar Hydrogen Generationen
dc.typeDissertationen
dc.contributor.departmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen
dc.contributor.committeememberAlshareef, Husam N.en
dc.contributor.committeememberSalama, Khaled N.en
dc.contributor.committeememberMerzaban, Jasmeenen
dc.contributor.committeememberGan, Qiaoqiangen
thesis.degree.disciplineElectrical Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id101754en
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