Перегляд за Автор "Gilmutdinova, Valeriia R."

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  • Ескіз
    Документ
    EFFECT OF AMMONIA VAPORS ON THE BREAKDOWN CHARACTERISTICS OF Si AND GaAs P-N JUNCTIONS
    (Одесский национальный университете имени И. И. Мечникова, 2012) Ptashchenko, Oleksandr O.; Ptashchenko, Fedir O.; Gilmutdinova, Valeriia R.; Dovganyuk, G. V.; Птащенко, Олександр Олександрович; Птащенко, Федір Олександрович; Гільмутдінова, Валерія Рафаїлівна; Довганюк, Г. В.; Гильмутдинова, Валерия Рафаэловна; Птащенко, Александр Александрович
    The influence of ammonia and water vapors on I-V characteristics of the reverse currents in Si and GaAs p-n junctions was studied. At most of the studied samples, the ammonia- and water vapors lover the breakdown voltage. At some devices an opposite effect was observed. This difference is due to dominance of different surface centers, which have donor or acceptor properties. And some p-n junctions exhibit a fixed breakdown voltage independently on the presence of ammonia and water vapors. This is due to the bulk location of the breakdown in these samples. Thus, the influence of ammonia vapors on the breakdown voltage provides some information on the localization of the breakdown and on the charge state of surface centers
  • Ескіз
    Документ
    Effect of deep centers on the time-resolved surface current induced by ammonia molecules adsorption in GaAs p-n junctions
    (Одесский национальный университет имени И. И. Мечникова, 2014) Ptashchenko, Oleksandr O.; Ptashchenko, Fedir O.; Gilmutdinova, Valeriia R.; Птащенко, Олександр Олександрович; Птащенко, Федір Олександрович; Гільмутдінова, Валерія Рафаїлівна; Птащенко, Александр Александрович; Птащенко, Федор Александрович; Гильмутдинова, Валерия Рафаэловна
    The time-dependence of the surface current in GaAs p-n structures after placing in concentrated wet ammonia vapors was studied. It is sown that the slope of measured current-time curves is non- monotonous. This effect is explained with taking into account presence of deep surface levels, which are filled, when the quasi-Fermi level is moving to the conduction band. An analysis of time-resolved measurements of surface current in GaAs p-n structures in wet ammonia vapors enabled to estimate depths of some surface levels. The depths of the main revealed surface levels are 0,206 eV, 0,185 eV, and 0,176 eV from с-band. In the interval of depths 0,176 eV - 0,185 eV surface levels are continuously distributed with practically constant density.
  • Ескіз
    Документ
    Effect of water vapors on the time-resolved surface current induced by ammonia molecules adsorption in GaAs p-n junctions
    (Одеський національний університет імені І. І. Мечникова, 2017) Ptashchenko, Oleksandr O.; Ptashchenko, Fedir O.; Gilmutdinova, Valeriia R.; Птащенко, Александр Александрович; Птащенко, Олександр Олександрович
    Supplement to the article published in Photoelectronics. – 2016. – № 25. – P. 126–131.
  • Ескіз
    Документ
    Effect of water vapors on the time-resolved surface current induced by ammonia molecules adsorption in GaAs p-n junctions
    (Одеський національний університет імені І. І. Мечникова, 2016) Ptashchenko, Oleksandr O.; Ptashchenko, Fedir O.; Gilmutdinova, Valeriia R.; Птащенко, Олександр Олександрович; Птащенко, Федір Олександрович; Гільмутдінова, Валерія Рафаїлівна; Птащенко, Александр Александрович; Птащенко, Федор Александрович; Гильмутдинова, Валерия Рафаэловна
    The time-resolved surface current in an n-conducting channel, due to ammonia and water molecules adsorption in GaAs p-n structures was studied. It is shown that the presence of water vapors in the ambient atmosphere strongly affects the current decay curves after the ammonia vapors removal.The results are explained in terms of a simple model taking into account a dynamic equilibrium between the free electrons in the conducting channel and electrons on slow surface centers. Each decay curve exponential component is due to the emptying of corresponding centers. The characteristic time of a current decay curve exponential component is determined by the depth and density of the corresponding surface levels, as well as the conducting channel thickness.
  • Ескіз
    Документ
    TUNNEL SURFACE CURRENT IN GaAs P-N JUNCTIONS INDUCED BY AMMONIA MOLECULES ADSORPTION
    (Одесский национальный университет имени И. И. Мечникова, 2013) Ptashchenko, Oleksandr O.; Ptashchenko, Fedir O.; Gilmutdinova, Valeriia R.; Птащенко, Олександр Олександрович; Птащенко, Федір Олександрович; Гільмутдінова, Валерія Рафаїлівна; Птащенко, Александр Александрович; Птащенко, Федор Александрович; Гильмутдинова, Валерия Рафаэловна
    The effect of a treatment in concentrated wet ammonia vapors on I-V characteristics of GaAs p-n junctions, measured in air and in ammonia vapors, was studied. Such a treatment strongly enhances the sensitivity of the surface current to the water- and ammonia vapors. In ammonia vapors of high enough partial pressure, a maximum in the forward branch of I-V characteristic appeared. The treated p-n junctions have higher gas sensitivity at reverse bias than at forward bias. This suggests that ammonia molecules adsorption, under sufficiently high NH3 partial pressure, forms in the p-n junction a surface conducting channel with degenerated electrons. And the observed maximum in the I-V characteristic is explained by tunnel injection of electrons from the conducting channel to the degenerated p+ region.