{"686593":{"#nid":"686593","#data":{"type":"event","title":"Ph.D. Dissertation Defense - Andr\u00e9 Perepeliuc","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003ETitle\u003C\/strong\u003E\u003Cem\u003E:\u0026nbsp; Hexagonal boron nitride for deep UV applications\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee:\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EDr. Abdallah Ougazzaden, ECE, Chair, Advisor\u003C\/p\u003E\u003Cp\u003EDr. Jean-Paul Salvestrini, ECE, Co-Advisor\u003C\/p\u003E\u003Cp\u003EDr. David Citrin, ECE\u003C\/p\u003E\u003Cp\u003EDr. Paul Voss, ECE\u003C\/p\u003E\u003Cp\u003EDr. Jennifer Hasler, ECE\u003C\/p\u003E\u003Cp\u003EDr. Luis Barrales-Mora, ME\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003ECurrent UVC LEDs based on AlGaN technology face major challenges, primarily due to the drastic reduction in conductivity caused by the difficulty of achieving efficient p-type doping as the aluminum content increases. Additionally, light extraction efficiency decreases with higher aluminum content. Hexagonal boron nitride (hBN) has emerged as a promising material to overcome these limitations. Owing to its unique properties, such as efficient p-type dopability, high UV transparency, strong luminescence, and excellent light extraction, hBN can potentially replace or complement conventional AlGaN layers. In particular, hBN can be integrated into AlGaN-based LEDs to form heterostructures with improved performance, simultaneously serving as both a hole injection layer and an electron blocking layer. The objective of this thesis is to demonstrate the feasibility of such heterostructures by fabricating operational UV LEDs that incorporate hBN as a hole injection layer. Moreover, during this PhD, an extraordinary phenomenon, extremely long-lived persistent photoconductivity in hBN at room temperature, has been discovered. This PPC effect, which can last for years, enables a novel photoinduced doping approach. Notably, the doping type can be tuned by varying the excitation wavelength. The understanding and utilization of this surprising effect constitute a central part of this work. The results presented in this thesis represent a significant step toward efficient UVC emission using hBN\/AlGaN heterostructures, providing a potential solution to the p-doping challenges at high aluminum content. Furthermore, the ability to optically induce both n-type and p-type doping in hBN opens the door to the realization of homojunction devices, paving the way toward entirely hBN-based LEDs with unprecedented efficiency, particularly since conventional doping techniques in hBN are still in their early stages.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Hexagonal boron nitride for deep UV applications "}],"uid":"28475","created_gmt":"2025-11-22 07:22:10","changed_gmt":"2025-11-22 07:23:18","author":"Daniela Staiculescu","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-11-28T15:00:00-05:00","event_time_end":"2025-11-28T17:00:00-05:00","event_time_end_last":"2025-11-28T17:00:00-05:00","gmt_time_start":"2025-11-28 20:00:00","gmt_time_end":"2025-11-28 22:00:00","gmt_time_end_last":"2025-11-28 22:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Pink Room, GTE (Metz, France)","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":""}}}