{"675564":{"#nid":"675564","#data":{"type":"event","title":"Ph.D. Dissertation Defense - Zhiyu Xu","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003ETitle\u003C\/strong\u003E\u003Cem\u003E:\u0026nbsp; Development, Fabrication and Characterization of III-Nitride Bipolar Devices: Rectifiers, Avalanche Photodiodes, and Laser Diodes\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EDr. Russell Dupuis, ECE, Chair, Advisor\u003C\/p\u003E\u003Cp\u003EDr. Shyh-Chiang Shen, ECE, Co-Advisor\u003C\/p\u003E\u003Cp\u003EDr. Wenshan Cai, ECE\u003C\/p\u003E\u003Cp\u003EDr. Ali Adibi, ECE\u003C\/p\u003E\u003Cp\u003EDr. Doug Yoder, ECE\u003C\/p\u003E\u003Cp\u003EDr. Nepomuk Otte, Physics\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EGaN as a wide-bandgap semiconductor material (~3.4eV) with high critical electrical field (~3MV\/cm) and direct bandgap, is a promising candidate for next-generation power devices and optoelectronics. In this thesis, the development of III-nitride bipolar devices is discussed. The studies and research mainly involve the design, fabrication process and characterization of vertical GaN p-i-n (PIN) rectifiers, GaN-based UV avalanche photodiodes (APDs) and UV laser diodes (LDs) based on the AlGaN\/GaN non-planar growth (NPG) method. Vertical GaN PIN rectifiers with nitrogen-implanted floating guard rings (FGRs) are designed and fabricated. A minimum low specific-on resistance (RONA) of 0.23 m\u03a9-cm2 was achieved with high reverse-bias breakdown voltage up to -1360V on the fabricated PIN rectifiers. High ION\/IOFF ratio was obtained \u0026gt;1012 at \u00b14 V, owning to the low reverse leakage and high forward-biased injection current. High optical avalanche gain and low reverse-bias leakage GaN APDs were developed by implementation of a ~1.8\u00b0 shallow bevel mesa, achieving an ultra-low leakage current density less than 10-9 A\/cm2 up to a reverse bias voltage of -70V and high avalanche multiplication gains \u0026gt; 107 under DUV illumination. The NPG on patterned (0001) GaN substrates was developed for growth of crack-free thick relatively high Al alloy composition AlGaN layers by suppression of tensile strain from AlGaN layer on GaN. The first UV pulsed-mode diode laser at ~370 nm based on AlGaN\/GaN NPG on GaN substrates was demonstrated with a 300 K lasing wavelength of 370 nm and the minimal threshold current density achieved of 8.8 kA\/cm2.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Development, Fabrication and Characterization of III-Nitride Bipolar Devices: Rectifiers, Avalanche Photodiodes, and Laser Diodes "}],"uid":"28475","created_gmt":"2024-07-23 00:36:23","changed_gmt":"2024-07-23 00:37:28","author":"Daniela Staiculescu","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2024-07-25T10:00:00-04:00","event_time_end":"2024-07-25T12:00:00-04:00","event_time_end_last":"2024-07-25T12:00:00-04:00","gmt_time_start":"2024-07-25 14:00:00","gmt_time_end":"2024-07-25 16:00:00","gmt_time_end_last":"2024-07-25 16:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Room W218, Van Leer","extras":[],"groups":[{"id":"434381","name":"ECE Ph.D. Dissertation Defenses"}],"categories":[],"keywords":[{"id":"100811","name":"Phd Defense"},{"id":"1808","name":"graduate students"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}