Research Areas

• Semiconductor Electronics and Nanotechnology
• Electron and Thermal Transport in Solid State Materials
• Multi-Scale Modeling of Nonequilibrium Electric-Field Driven Phenomena
• Bioelectrics and Bio-medical Engineering

 

Semiconductor Electronics and Nanotechnology

• We were one of the first groups to model electron transport in wide bandgap semiconductors such as SiC and GaN based on Monte Carlo methods. Other contributions were towards robust photoconductive switching for high energy, high-voltage applications, Performance improvements in GaN-based transistors and HEMTS.
• (SiC à J. Appl. Phys. 78, 3492, 1995; J. Appl. Phys. 78, 5518, 1995; Solid State Electronics 38, 1911, 1995; Appl. Phys. Lett. 72, 2156, 1998; J. Appl. Phys. 85, 3701, 1999; J. Appl. Phys. 85, 7935, 1999;J. Appl. Phys. 86, 5060, 1999; J. Appl. Phys. 88, 829, 2000; Journal of Applied Physics 118, 095701, 2015; IEEE Trans. Electron Devices 63, 3171, 2016; Journ. Phys. D 50, 135104, 2017).
• (GaN à Appl. Phys. Lett. 64, 223, 1994; Appl. Phy. Lett. 64, 3611, 1994; Physica Status Solidi B 204, 106, 1997; J. Appl. Phys. 88, 829, 2000; J. Appl. Phys. 90, 3030, 2001; IEEE Trans. Electr. Dev. ED-49, 1511, 2002; J. Appl. Phys. 93, 4836, 2003; J. Appl. Phys. 93, 10046, 2003; Journ. Applied Phys. 129, 195703, 2021; MDPI Electronics 11, 2997, 2022).

 

Electron and Thermal Transport in Solid State Materials

• Important physics-based concepts were developed for electric field driven response in electronic devices, detectors, applications to high current electron emitters with inclusion of quantum effects as necessary. Many body and non-equilibrium phonon effects in devices were studied and contributions reported in the literature. Too many to name or discuss, but a few representative published papers are given below:

(Phys. Rev B 39, 1180, 1989; Phys. Rev. B 39, 1446, 1989; Solid State Electronics 32, 1597, 1989; J. Appl. Phys. 66, 428, 1989; Phys. Rev. B 41, 9899, 1990; Phys. Rev. B 42, 5685, 1990; Computer Phys. Communications 67, 119, 1991; Phys. Rev. B 43, 9734, 1991; Appl. Phys. Lett. 58, 2369, 1991; Semiconductor Science and Technology 7, B243, 1992; Appl. Phys. Lett. 59, 1572, 1991; J. Appl. Phys. 71, 3827, 1992; Applied Physics Letters 62, 2075, 1993; Appl. Phys. Lett. 64, 223, 1994; Appl. Phys. Lett. 68, 2990, 1996; Appl. Phys. Lett. 69, 1786, 1996; J. Appl. Phys. 81, 406, 1997; Physica Status Solidi B 204, 106, 1997; J. Appl. Phys. 83, 5543, 1998; J. Appl. Phys. 88, 265, 2000; J. Appl. Phys. 88, 829, 2000; Journ. Appl. Phys. 113, 184504, 2013; AIP Advances 5, 017103, 2015; AIP Advances 5, 127237, 2015; Journ. Phys. D 50, 185202, 2017; Scientific Reports (Nature Publishing) 13, 8260, 2023).

 

Multi-Scale Modeling of Nonequilibrium Electric-Field Driven Phenomena

• The underlying theme and unifying focus of his investigations and contributions have been effects, mechanisms, and inherent processes driven by high electric fields in various applications. The broad themes and categories encompassing this body of work roughly falls under the following areas: (i) high electric fields which enable nonlinear and quantum effects, (ii) ultrashort timescales dominated by nonequilibrium phenomena, and (iii) regimes where dynamic screening due to high charge densities can influence outcomes. Some published references outlining our numerous, varied contributions is given below:

(J. Appl. Phys. 74, 1568, 1993; Appl. Phys. Lett. 69, 1786, 1996; J. Appl. Physics 84, 3197, 1998; J. Appl. Phys. 88, 817, 2000; J. Appl. Phys. 91, 1331, 2002; J. Appl. Phys. 96, 5129, 2004; J. Phys. D 39, 359, 2006; Journ. Amer. Ceramic Soc. 91, 1188, 2008; Plasma Sources Science and Technology 25, 025024, 2016; Physics of Plasmas 25, 022109, 2018; Journ. Appl. Phys. 128, 223302, 2020; J. Phys D: Applied Physics 55, 045202, 2022; Scientific Reports (Nature Publishing) 12, 15808, 2022; J. Applied Phys. 132, 213304, 2022; Frontiers in Materials 11, 1145425, 2023; Scientific Reports (Nature Publishing) 13, 8260, 2023; Journ. Appl. Phys. 135, 223301, 2024; Physics of Plasmas 32, 013512, 2025; Journ. Appl. Physics 138, 143303, 2025).

 

Bioelectrics and Bio-medical Engineering

• Contributions in this area hinge on the application of nanosecond, high intensity (~100 kV/cm) electric field pulses for cellular- and intra-cellular bio-manipulation. Using physics-based computational techniques that have included molecular details and interactions, field-dependent changes in bio-membrane conductivity, thermal changes, and spatial variability, some of the important applications are towards electro-chemotherapy and drug delivery in cells and tissues. This is brought about by causing “electroporation” in cells that facilitates drug and gene delivery. Other uses of electric fields in bio-medicine studies by Dr. Joshi’s group includes cellular electro-manipulation with nanoparticle-based enhancements [Physical Review E 103, 022402, 2021)], or the frequency selective targeting of tumor cells by radiofrequency stimulation (IEEE Trans. Biomedical Engineering 71, 114, 2024); Journal of Applied Physics 133, 244701, 2023]. Contributions in this area are briefly summarized below by indicating the various publications:

(Bio-engineering and Bio-electrics à Phys. Review E 64, 11913, 2001; Physiological Measurement 25, 1077, 2004; Phys. Rev. E 72, 031902, 2005; Biophysical Journal 90, 3608, 2006; Phys. Rev. E 75, 041920, 2007; IEEE Trans. Biomedical Engineering 55, 1391, 2008; IEEE Trans. Biomedical Engineering 56, 1617, 2009; Bioelectrochemistry 79, 179, 2010; Critical Reviews in Bio-Medical Engineering 38, 255, 2010; "Electromagnetic Fields in Biological Systems," CRC Press, Boca Raton, 2011, pp. 71-114, ISBN: 9781439859995; European Biophysics Journal 40, 947, 2011; Physical Review E 87, 032704, 2013; Biochimica et Biophysica Acta – Biomembranes 1838, 902, 2014; Physical Review Applied 7, 024003, 2017; AIP Advances 9, 045006, 2019; Ultrashort Electric Pulse Effects in Biology and Medicine (Springer, New York, 2021), ISBN: 978-981-10-5113-5; J. Appl. Phys. 133, 244701, 2023; IEEE Trans. Biomed. Engr. 71, 114, 2024; IEEE Access 12, 8004, 2024; Scientific Reports 14, 23854, 2024; Bioengineering 12, 372, 2025; IEEE Trans. Biomed. Engr. 72, 768, 2025).

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