Optoelectronics with Carbon Nanotubes

dc.contributor.authorKinoshita, Megumien_US
dc.contributor.otherDepartment of Physicsen_US
dc.description.abstractThe carbon nanotube is a promising material for future micro- and nano-scale electronics because of its unique electronic properties, high carrier mobility and extraordinary capacity for high current density. In particular, semiconducting carbon nanotubes are direct bandgap materials with a typical energy gap in the order of 1 eV, which means they emit light in the near-infrared range, making them an attractive option in telecommunications applications. However, there have been few systematic investigations of electrically-induced light emission (i.e. electroluminescence) from carbon nanotubes, and their emission properties are not well understood. In this dissertation, we explore the characteristics of electroluminescence in three different types of carbon-nanotube devices. The first is a single-tube field-effect transistor (CNTFET), whose emission has previously been found to have a very broad spectral shape and low emission efficiency. We analyze the spectral shape in detail, which reveals that a high electric field near metal contacts contributes most to the bias-dependent component of broadening, in addition to smaller contributions from tube nonuniformity, inelastic scattering of phonons, high temperature, etc. In the second part of the study, single-tube light-emitting diodes are constructed by employing a split top-gate scheme. The split gate creates p- and n-doped regions electrostatically, so that electrons and holes combine between the two sections and can decay radiatively. This configuration creates electron-hole pairs under much lower electric fields and gives us a greater control over carrier distribution in the device channel, resulting in much narrower spectral linewidths and an emission intensity several orders of magnitude larger than that of CNTFETs. The much better signal-to-noise also leads to the observation of emission from defect-induced states. Finally, we extend the idea of the single-tube p-n diode and fabricate CNT film diodes from many purified tubes aligned in parallel. While the operating principle is somewhat different from that of single-tube diodes because of the presence of metallic tubes in the material, the film diodes nonetheless show a rectifying behavior and much greater light intensity than single-tube devices. With their superior light output and robustness, they bring us one step closer to a real-world application of carbon nanotubes optoelectronics.en_US
dc.description.advisorAdvisor(s): Emilio E. Mendez. Committee Member(s): Philip B. Allen; Harold J. Metcalf; Stanislaus Wong.en_US
dc.description.sponsorshipStony Brook University Libraries. SBU Graduate School in Department of Physics. Lawrence Martin (Dean of Graduate School).en_US
dc.formatElectronic Resourceen_US
dc.publisherThe Graduate School, Stony Brook University: Stony Brook, NY.en_US
dc.subject.otherCarbon Nanostructures, Condensed Matter - Mesoscale and Nanoscale Physics, Nano-Opticsen_US
dc.titleOptoelectronics with Carbon Nanotubesen_US
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