Our Research

Our group’s research is dedicated to the advancement of nitride wide bandgap semiconductors (GaN, AlN, AlGaN, InGaN, and InAlGaN). These semiconductors are recognized as a very important technological material system for the fabrication of optoelectronic devices operating in the blue and UV spectral regions and electronic devices capable of operating under high power and high temperature conditions.  Our group’s concentration areas are epitaxial growth, micro- and nano-structure and device fabrication, and fundamental optical and transport investigations.  Examples of our research topics are highlighted below:

·        We were one of the first few in the world to employ picosecond time-resolved photoluminescence (PL) to study mechanisms of optical transitions, LED emission, and lasing in III-nitrides;

·        We were the first to utilize the persistent photoconductivity effect to probe the carrier localization in semiconductor alloys and the nature of impurities in GaN and AlGaN;

·        We have pioneered the growth and fabrication of UV & blue micro- and nano-size photonic structures and devices based on III-nitrides, including micro-size emitters, submicron waveguides, micropyramids,  microlens arrays, and photonic crystals – laid the groundwork for achieving photonic integrated circuits which are active in blue and UV regions.

·        We succeeded in interconnecting together hundreds of microdisk LEDs (disk size on the order of 10 mm in diameter) made from InGaN/GaN QWs and demonstrated boosted quantum efficiencies in interconnected microdisk LEDs - made the transition of tiny micro-size emitters from basic research to practical device components;

·        We have successfully fabricated the world’s first prototype semiconductor blue microdisplay based on nitrides. 

·        We are one the few to achieve highly conductive n-type Al_xGa_1-xN alloys of high Al contents (for x up to 1) and p-type conduction in AlGaN alloys (1 micron thick films) for AlN fraction up to 27%.  We have also produced AlN epilayers with very efficient band-edge PL emission by MOCVD.

 Find out more about our research at our Research Areas page.

Our research is supported by: NSF, DOE, ARO, AFOSR,and DARPA

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