@article{borysenko_mullen_barry_paul_semenov_zavada_nardelli_kim_2010, title={First-principles analysis of electron-phonon interactions in graphene}, volume={81}, ISSN={1098-0121 1550-235X}, url={http://dx.doi.org/10.1103/PhysRevB.81.121412}, DOI={10.1103/physrevb.81.121412}, abstractNote={The electron-phonon interaction in monolayer graphene is investigated using density-functional perturbation theory. The results indicate that the electron-phonon interaction strength is of comparable magnitude for all four in-plane phonon branches and must be considered simultaneously. Moreover, the calculated scattering rates suggest an acoustic-phonon contribution that is much weaker than previously thought, revealing an important role of optical phonons even at low energies. Accordingly it is predicted, in good agreement with a recent measurement, that the intrinsic mobility of graphene may be more than an order of magnitude larger than the already high values reported in suspended samples.}, number={12}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Borysenko, K. M. and Mullen, J. T. and Barry, E. A. and Paul, S. and Semenov, Y. G. and Zavada, J. M. and Nardelli, M. Buongiorno and Kim, K. W.}, year={2010}, month={Mar} }
 @article{barry_sokolov_kim_trew_2010, title={Large-Signal Analysis of Terahertz Generation in Submicrometer GaN Diodes}, volume={10}, ISSN={1530-437X 1558-1748}, url={http://dx.doi.org/10.1109/JSEN.2009.2038132}, DOI={10.1109/jsen.2009.2038132}, abstractNote={The conditions for microwave power generation in a submicrometer GaN diode, with a relatively lightly doped active channel, coupled to an external resonant circuit are investigated. Applying a high-field electron transport model based on the local quasi-static approximation, we show that oscillations in group III-nitride diodes can be supported in the terahertz-frequency range near the limited space-charge accumulation regime. The shape of the diode voltage and electronic current waveforms are examined in terms of the circuit parameters and operating frequencies over the bandwidth of active generation. Based on a Fourier series analysis of the diode voltage and current, the generated power and dc-to-RF conversion efficiency at the fundamental and the second or higher order harmonic frequencies are estimated. The calculation results clearly indicate that submicrometer GaN diodes (channel doping of 1 × 1017 cm-3) can achieve large output powers (> 1 W) in the absence of Gunn domain formation, over a wide range of frequencies, near 0.5 THz.}, number={3}, journal={IEEE Sensors Journal}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Barry, E. A. and Sokolov, V. N. and Kim, K. W. and Trew, R. J.}, year={2010}, month={Mar}, pages={765–771} }
 @article{li_barry_zavada_buongiorno nardelli_kim_2010, title={Surface polar phonon dominated electron transport in graphene}, volume={97}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.3525606}, DOI={10.1063/1.3525606}, abstractNote={The effects of surface polar phonons on the electronic transport properties of monolayer graphene are studied by using a Monte Carlo simulation. Specifically, the low-field electron mobility and saturation velocity are examined for different substrates (SiC, SiO2, and HfO2) in comparison to the intrinsic case. While the results show that the low-field mobility can be substantially reduced by the introduction of surface polar phonon scattering, corresponding degradation of the saturation velocity is not observed for all three substrates at room temperature. It is also found that surface polar phonons can influence graphene’s electrical resistivity even at low temperature, leading potentially to inaccurate estimation of the acoustic phonon deformation potential constant.}, number={23}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Li, X. and Barry, E. A. and Zavada, J. M. and Buongiorno Nardelli, M. and Kim, K. W.}, year={2010}, month={Dec}, pages={232105} }
 @article{barry_sokolov_kim_trew_2009, title={Terahertz generation in GaN diodes operating in pulsed regime limited by self-heating}, volume={94}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.3147217}, DOI={10.1063/1.3147217}, abstractNote={The conditions for pulsed regime operation of terahertz power generation in vertical nanoscale GaN-based diodes are investigated via self-consistent simulation of the high-field electron transport in the active channel and thermal transport in the entire device structure. The combined electrothermal model allows for a detailed analysis of the dynamical local distributions of the electric field, drift-velocity, and lattice temperature. We show that stable generation is achievable with a self-heating limited output power of 2.25 W at an operation frequency of 0.71 THz for a pulse width of 3 ns with a few tens of nanosecond duty cycle.}, number={22}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Barry, E. A. and Sokolov, V. N. and Kim, K. W. and Trew, R. J.}, year={2009}, month={Jun}, pages={222106} }
 @article{barry_sokolov_kim_trew_2008, title={Terahertz generation in GaN diodes in the limited space-charge accumulation mode}, volume={103}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.2946717}, DOI={10.1063/1.2946717}, abstractNote={The conditions for terahertz power generation are investigated theoretically in a nanoscale GaN-based diode coupled to an external resonant circuit for operation in the limited space-charge accumulation (LSA) mode under the high-field transport regime. The generation criteria are revisited in terms of a phase plane analysis of the diode high-field transport and circuit equations. Based on a Fourier series analysis, the waveforms of the diode voltage and current are examined and the generated power and conversion efficiencies are estimated at the fundamental and lowest harmonic frequencies. The advantages of group-III nitride LSA diodes are elucidated including their ability to simultaneously achieve large output powers (>10 mW) and high dc-to-rf conversion efficiencies (>1%) over a wide range of frequencies near 1 THz.}, number={12}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Barry, E. A. and Sokolov, V. N. and Kim, K. W. and Trew, R. J.}, year={2008}, month={Jun}, pages={126101} }
 @article{barry_kiselev_kim_2003, title={Electron spin relaxation under drift in GaAs}, volume={82}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.1578180}, DOI={10.1063/1.1578180}, abstractNote={Based on a Monte Carlo method, we investigate the influence of transport conditions on the electron spin relaxation in GaAs. The decay of initial electron spin polarization is calculated as a function of distance under the presence of moderate drift fields and/or nonzero injection energies. For relatively low fields (a couple of kV/cm), a substantial amount of spin polarization is preserved for several microns at 300 K. However, it is also found that the spin relaxation rate increases rapidly with the drift field, scaling as the square of the electron wave vector in the direction of the field. When the electrons are injected with a high energy, a pronounced decrease is observed in the spin relaxation length due to an initial increase in the spin precession frequency. Hence, high-field or high-energy transport conditions may not be desirable for spin-based devices.}, number={21}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Barry, E. A. and Kiselev, A. A. and Kim, K. W.}, year={2003}, month={May}, pages={3686–3688} }
 @article{barry_kim_kochelap_2002, title={Hot electrons in group-III nitrides at moderate electric fields}, volume={80}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.1464666}, DOI={10.1063/1.1464666}, abstractNote={By the use of the Monte Carlo method, we studied the distribution function and the basic characteristics of hot electrons in InN, GaN, and AlN under moderate electric fields. We found that in relatively low fields (of the order of kV/cm) the optical phonon emission dominates in the electron kinetics. This strongly inelastic process gives rise to a spindle-shaped distribution function and an extended portion of a quasisaturation of the current–voltage (I–V) characteristics (the streaming-like regime). Formation of this regime is induced by a suppression of the electron spreading over the momenta perpendicular to the electric field. We prove that this is a universal character of the hot electron behavior for all three nitrides. The effects can be detected by the measurement of the I–V characteristics, or the thermopower of hot electrons in the transverse direction.}, number={13}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Barry, E. A. and Kim, K. W. and Kochelap, V. A.}, year={2002}, month={Apr}, pages={2317–2319} }
 @article{barry_kim_kochelap_2001, title={Group-III nitrides hot electron effects in moderate electric fields}, volume={228}, DOI={10.1002/1521-3951(200111)228:2<571::aid-pssb571>3.0.co;2-i}, abstractNote={We studied the distribution function and basic characteristics of hot electrons in InN, GaN and AlN under moderate electric fields, and found that in relatively low fields (of the order of kV/cm) the optical phonon emission dominates the electron kinetics. This strongly inelastic process gives rise to a spindle-shaped distribution function and an extended portion of quasi-saturation of the current-voltage characteristics (the streaming-like regime). We prove that this hot electron regime holds for all three nitrides. We suggest that the effects can be detected by the measurement of the I-V characteristics, or the thermopower of hot electrons in the transverse direction.}, number={2}, journal={Physica Status Solidi. B, Basic Solid State Physics}, author={Barry, E. A. and Kim, K. W. and Kochelap, V. A.}, year={2001}, pages={571–574} }