Перегляд за автором "Shulika, O."

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  • Зображення мініатюри
    Публікація
    Joint influence of internal fields and indium surface segregation on band structure in ingan/gan single quantum well
    (Photoelectronics, 2010) Klymenko, M.; Petrov, S.; Shulika, O.
    In this paper, authors investigate the influence of the indium surface segregation and piezoelectric polarization on the band structure of the InGaN/GaN single quantum well. The obtained results evidence that the indium surface segregation leads to the blue shift of the transition energy (70 meV for the segregation length 1nm at both heterointerfaces) while the piezoelectric polarization itself causes the read shift. Joint action of both effects influence on the potential profile determining the linear dependence of the transition energy on the width of the quantum well. The piezoelectric polarization is prevailed for the high indium amount, and the indium surface segregation is dominated for the low indium amount in the In(x)Ga(1-x)N alloy.
  • Зображення мініатюри
    Публікація
    Theoretical Study of Optical Transition Matrix Elements in InGaN/GaN SQW Subject to Indium Surface Segregation
    (Journal of Selected Topics in Quantum Electronics, 2011) Klymenko, M.; Shulika, O.; Sukhoivanov, I.
    We investigate the dependence of dipole matrix elements for InGaN/GaN single quantum well structures on the indium surface segregation. Obtained results show that the influence of the surface segregation on the dipole matrix element is not equal for all optical transition. This effect results from the joint action of the piezoelectric polarization and indium surface segregation which change selection rules. In addition, surface segregations at each interface of the quantum well have different impact on optical characteristics depending on the direction of the piezoelectric polarization. The effect of the surface segregation has been estimated applying the global sensitivity analysis in the frame of six-band approximation for the valence band and parabolic approximation for the conduction band.