Research discoveries that have translated to applications

 

We delight in every tiny scientific nugget we uncover in our daily research. Some of these unexpectedly lead to practical applications.Here is a list of some that we were fortunate to see go from scratching our heads to understand mysterious data collected in the lab, to projects and products in the industry.

 

1.     Discovery of distributed polarization doping for mobile electrons (n-type doping) in wide bandgap semiconductors in 2002 (link), and its use for the first PolFET in 2002 (chapter 5 of my PhD thesis, and patent).See how our discovery has enabled transistors pursued by industry here.

 

2.     Discovery of distributed polarization doping for mobile holes (p-type doping) in wide bandgap semiconductors in 2009 (link) and its use in UV LEDs (patent).The p-type doping of GaN with the acceptor Mg that enabled blue LEDs and lasers in 1990s and 2000s (see the 2014 Physics Nobel Lectures 1, 2, 3) was insufficient to realize UV lasers with wider bandgap AlGaN and AlN. See how our discovery of distributed polarization doping was used by industry to realize the first ever electrically injected deep-UV semiconductor laser in 2019 (link) and its CW operation in 2022 (link).

 

3.     Discovery of ultrahigh density 2D hole gases at undoped wide bandgap semiconductor heterojunctions due to polarization discontinuity in 2019 (link). Even though p-type doping of GaN with the acceptor Mg had enabled blue LEDs and lasers in 1990s and 2000s (see the 2014 Physics Nobel Lectures 1, 2, 3), the hole density remained insufficient for high-performance p-channel transistors.Our 2019 discovery of the ultrahigh density 2D hole gases (see patent) enabled us to demonstrate the first ever RF p-channel GaN transistors in 2020 (link). Also see our p-FET device patent.††

 

 

Research inventions with high application potential in the near-future

 

While some of our groupís research have seen applications in industry, theory, modeling, and a bit of leap of faith allow us to conceive devices outside of available materials and processing technology of the time.Here are a few examples.Over time, ingenuity of the research community has brought some of them to fruition.

 

1.     GNRTFETs: 2008 proposal, and a realization.Takes advantage of the unique property of 2D materials for energy-efficient electronic switches.

 

2.     TMDFETs: 2012 realization in collaboration with Samsung of the first 2D material channel FETs to show current saturation and near ideal switching.

 

3.     SymFETs: 2012 theory, proposal, and a realization.Uses interlayer tunneling between 2D materials.Related to BISFETs, and Moire lattices in twisted 2D layers.

 

4.     ThinTFETs: 2014 proposal, and a realization.Uses interlayer tunneling between 2D materials for energy-efficient electronic switches.

 

5.     PiezoFETs: 2014 proposal using active gate barriers in polar semiconductors.

 

6.     GaN TFETs: 2016 proposal, patent, and a 2020 realization.Uses high internal fields in polar semiconductors for energy-efficient electronic switches.

 

7.     LEFETs: 2018 patent, and a realization.LEDs and FETs in the same device for photonic communications and LiFi.

 

8.     GOFETs: 2018 patent and a realization.Gallium oxide power transistors for energy efficient electronics.

 

9.     UV LEDs/Lasers: 2018 patent and realizations using quantum structures and distributed polarization doping with GaN quantum dots in 2014 (link), and ultrathin GaN quantum wells in 2017 (link, link).

 

10.  UV LEDs/Lasers: 2018 patent, and realizations using distributed polarization doping with tunnel junctions in 2017 (link), and distributed polarization p-doping in 2017 (link).

 

11.  SOTFETs: 2020 collaborative proposal of the Spin-orbit torque FET as a logic/memory hybrid device for associative memories (link), and materials to realize them (link).

 

12.  FerroHEMTs: 2022 first realization. Polar semiconductor based ferroelectric transistors for RF/mm-wave electronic communications, digital electronics for logic, and non-volatility for memory - all in one device!

 

Stay tuned for more!

 

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