@article{sirenko_kim_stroscio_1997, title={Near-surface electrons and acoustic phonons: Energy and momentum relaxation}, volume={56}, ISSN={0163-1829 1095-3795}, url={http://dx.doi.org/10.1103/PhysRevB.56.15770}, DOI={10.1103/physrevb.56.15770}, abstractNote={We study energy and momentum relaxation of a two-dimensional (2D) electron channel located at a finite distance $\mathcal{l}$ from a free crystal surface. The interaction with a complete set of bulklike, totally reflected, and Rayleigh acoustic phonon modes is taken into account. In most cases of interest the relaxation rates have the same temperature dependence as for 2D or bulk electrons interacting with bulk phonons. Numerical calculations demonstrate that the presence of a surface results in approximately a 10% modification of scattering rates in the high-temperature region. In the opposite limit (Bloch-Gr\"uneisen regime), the contribution of the surface phonons may dominate over that of bulklike modes. Oscillations of the relaxation rates as a function of the distance $\mathcal{l}$ between the electron channel and the surface are also predicted.}, number={24}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Sirenko, Yuri M. and Kim, K. W. and Stroscio, Michael A.}, year={1997}, month={Dec}, pages={15770–15781} }
@article{wang_jeon_sirenko_kim_1997, title={Piezoelectric effect on optical properties of pseudomorphically strained wurtzite GaN quantum wells}, volume={9}, ISSN={1041-1135 1941-0174}, url={http://dx.doi.org/10.1109/68.584971}, DOI={10.1109/68.584971}, abstractNote={The presence of internal strain in wurtzite quantum-well (QW) structures may lead to the generation of large polarization fields. These piezoelectric fields cause a spatial separation of the electrons and holes inside the QW to screen the internal fields. A self-consistent calculation of optical gain and the corresponding differential gain is presented in pseudomorphically strained GaN quantum wells as a function of carrier density. Based on the local exchange-correlation potential, electron and hole band structures are obtained by coupling Poisson's equation with an effective-mass Schrodinger equation in the conduction band and an envelope-function (or k/spl middot/p) Hamiltonian in the valence band. Our calculations show that self-consistent calculations including the piezoelectric effects are essential for accurate description of strained wurtzite QW structures.}, number={6}, journal={IEEE Photonics Technology Letters}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Wang, Jin and Jeon, J.B. and Sirenko, Yu.M. and Kim, K.W.}, year={1997}, month={Jun}, pages={728–730} }
@article{jeon_lee_sirenko_kim_littlejohn_1997, title={Strain effects on optical gain in wurtzite GaN}, volume={82}, ISSN={0021-8979 1089-7550}, url={http://dx.doi.org/10.1063/1.365824}, DOI={10.1063/1.365824}, abstractNote={Strain effects on optical gain in hexagonal bulk GaN are calculated and explained in terms of the change in the effective hexagonal crystal field component. Qualitatively, even unstrained wurtzite structures correspond to cubic crystals with a proper biaxial stress applied. Such biaxial stress results in effective tensile deformation along the c axis ([111] direction in cubic crystals) and compressive strain in the perpendicular plane. Therefore, the light mode with a polarization vector parallel to the c axis is suppressed, while the mode with a perpendicular polarization is enhanced in wurtzite structures. Thus, compared to cubic structures with similar material parameters, a strong optical anisotropy of wurtzites results in enhanced gain for certain light polarizations, which make wurtzite structures superior for lower-threshold lasing. These qualitative arguments are illustrated by numerical calculations of optical gain in biaxially strained wurtzite GaN, based on a 6×6 envelope-function Hamiltonian.}, number={1}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Jeon, J. B. and Lee, B. C. and Sirenko, Yu. M. and Kim, K. W. and Littlejohn, M. A.}, year={1997}, month={Jul}, pages={386–391} }
@article{sirenko_jeon_lee_kim_littlejohn_stroscio_1997, title={Valence band spectra in pseudomorphically strained wurtzite quantum wells}, volume={22}, ISSN={0749-6036}, url={http://dx.doi.org/10.1006/spmi.1996.0215}, DOI={10.1006/spmi.1996.0215}, abstractNote={A theory for the effects of size quantization and strain on the hole energy spectra in wurtzite AlGaN/GaN/AlGaN quantum wells is presented. The subband structure and dispersion relations for holes in pseudomorphically strained rectangular wells are obtained using an analytical solution of Schrödinger's equation with 3 × 3 matrix Hamiltonian blocks. The effects of strain are interpreted using an analogy between würzite structures and prestrained zincblende crystals.}, number={2}, journal={Superlattices and Microstructures}, publisher={Elsevier BV}, author={Sirenko, Yu.M. and Jeon, J.-B. and Lee, B.C. and Kim, K.W. and Littlejohn, M.A. and Stroscio, M.A.}, year={1997}, month={Sep}, pages={195–198} }