Publications

Abstract not provided.

Nanowires based on the III nitride materials system have attracted attention as potential nanoscale building blocks in optoelectronics, sensing, and electronics. However, before such applications can be realized, several challenges exist in the areas of controlled and ordered nanowire synthesis, fabrication of advanced nanowire heterostructures, and understanding and controlling the nanowire electrical and optical properties. Here, recent work is presented involving the aligned growth of GaN and III-nitride core-shell nanowires, along with extensive results providing insights into the nanowire properties obtained using advanced electrical, optical and structural characterization techniques.

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The proposed work seeks to demonstrate and understand new phenomena in novel, freestanding III-nitride core-shell nanowires, including 1D and 2D electron gas formation and properties, and to investigate the role of surfaces and heterointerfaces on the transport and optical properties of nanowires, using a combined experimental and theoretical approach. Obtaining an understanding of these phenomena will be a critical step that will allow development of novel, ultrafast and ultraefficient nanowire-based electronic and photonic devices.

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We present the results of a three year LDRD project which has focused on the development of novel, compact, ultraviolet solid-state sources and fluorescence-based sensing platforms that apply such devices to the sensing of biological and nuclear materials. We describe our development of 270-280 nm AlGaN-based semiconductor UV LEDs with performance suitable for evaluation in biosensor platforms as well as our development efforts towards the realization of a 340 nm AlGaN-based laser diode technology. We further review our sensor development efforts, including evaluation of the efficacy of using modulated LED excitation and phase sensitive detection techniques for fluorescence detection of bio molecules and uranyl-containing compounds.