Wide Bandgap III-Nitride Micro- and Nano-Photonics

AlGaN alloys with high Al contents, covering from 350 nm to 200 nm, are ideal materials for the development of efficient ultraviolet (UV) light sources/sensors. There are many problems and questions that still stand in the way of the practical device implementation of UV photonic devices. Among these, the attainment of highly conductive Al-rich AlGaN remains one of the biggest obstacles for the III-nitride research. The objectives of this program were to address some of the fundamental material and device issues and to explore potential applications of III-nitrides for UV micro- and nano-photonic devices. The KSU team has achieved 1. n-type Al-rich AlGaN alloys with record high conductivities. 2. converted highly insulating AlN to n-type conductive AlN by Si doping. 3. nano-fabrication and characterization of III-nitride photonic crystals (PC) and demonstrated the first current-injected III-nitride PC emitter operating below 330 nm. 4. p-type conduction in Al-rich AlxGa1-xN for x up to 0.7. 5. nano-fabrication of deep UV photonic crystals on AlN wafers. 6. achieved 280 nm UV LEDs that are among the best in the world. 7. demonstrated the operation of 200 nm DUV Schottky detectors based on AlN having a detectivity that is comparable to those of photomultiplier tubes.
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