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Nanostructured Materials and Devices

Our group investigates charged liquid cluster beam generation for the fabrication of highly structured thin films, nanoparticles, nanofibers, and in-situ pattern generation; growth of group-III nitride semiconductors and fabrication of power electronic devices using plasma-assisted MBE; development of novel techniques for thin film deposition and fabrication of nanotubes, nanofibers and nanowires using plasmas, charged particles, electrostatic spraying, CVD and their combinations; novel flat panel displays including FED and OLED.

Research Interests

Plasma-assisted Molecular-beam Epitaxy (PAMBE)

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Design, modeling, simulation, and experimental validation of vertical high-power GaN devices and edge termination techniques using plasma-assisted molecular-beam epitaxy enabled selective-area growth (PAMBE-SAG) protocol. The unique epitaxial growth method helps ensure smooth, well-defined, and defect-free p-n interfaces and sidewalls, a key requirement for high-performance GaN power devices, by eschewing such defect generating conventional processing methods such as ion implantation and inductively-coupled plasma reactive-ion etching (ICP-RIE).

Highlighted Projects

  • High-Performance GaN Vertical p-i-n Diodes via Silicon Nitride Shadowed Selective-Area Growth and Optimized FGR-and JTE-Based Edge Termination (Link)

  • Design of selective-area growth compatible fully-vertical GaN p-i-n diodes with dielectric vertical sidewall appended edge termination schemes (Link). 

Flow-limited Field-injection Electrostatic Spraying (FFESS)

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Flow-limited field injection electrostatic spraying (FFESS) has been developed as an improved technique for the controlled deposition/coating of polymeric and oxide materials. FFESS creates these coatings using field-injection to charge precursor solutions which disperse into a spray of nano-sized droplets which uniformly coat substrates in the desired material. Possible applications lead to the deployment of high-density sensor networks which can be applied to various global issues from health to agriculture to climate change.

 

The most recent study involves the investigation of the viability for the production of exotic oxide materials such as topological insulators. This is facilitated by the flexibility and control over material stoichiometry and stability provided by solution-phase processing. These materials are integral for applications such as fault-tolerant quantum computing and will not be achievable without the processing control facilitated by technologies like FFESS.

Highlighted Projects

  • Investigation of optical properties of aluminum-doped zinc oxide films via flow-limited field-injection electrostatic spraying (Link). 

  • Controlloing surface nano-structure using flow-limited field-injection electrostatic spraying (FFESS) of poly(D,L-lactide-co-glycolide) (Link).