Fergana, Uzbekistan

Ferghana Polytechnical Institute

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Fergana, Uzbekistan
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Sulaimonov K.M.,Ferghana Polytechnical Institute
Technical Physics | Year: 2017

It has been found that the resistance of the (Bi0.3Sb0.7)2Te3 porous polycrystalline film fabricated by thermal vacuum evaporation at substrate temperature Ts ≤ 363 K drastically decreases near the threshold AC frequency ω0 ≈ 105 Hz as low as the resistance of dense films with Ts ≈ 423 K. After the action of N ≈ 105 cycles of mechanical deformation with amplitude ε = ±1 × 10–3 a.u., the film resistance increases by 1.5 times and the threshold frequency decreases in almost 102 times, which can qualitatively be accounted for by the model of microcontacting blocks. © 2017, Pleiades Publishing, Ltd.


Atakulov S.B.,Fergana State University | Zaynolobidinova S.M.,Fergana State University | Nabiev G.A.,Ferghana Polytechnical Institute | Nabiyev M.B.,Fergana State University | Yuldashev A.A.,Ferghana Polytechnical Institute
Semiconductors | Year: 2013

The mobility of nondegenerate electrons in quasi-single-crystal and polycrystalline PbTe films is experimentally investigated. The results obtained are compared with the data for bulk crystals at the same charge-carrier concentration. Under the assumption of limitation of the charge-carrier mobility by intercrystallite potential barriers, electron transport in an electric field is theoretically considered. The theoretical results are in good agreement with the experiment. © 2013 Pleiades Publishing, Ltd.


Atakulov S.B.,Fergana State University | Zainolobidinova S.M.,Fergana State University | Nabiev G.A.,Ferghana Polytechnical Institute | Tukhtamatov O.A.,Fergana State University
Semiconductors | Year: 2012

For three groups of polycrystalline semiconductor films, an experimental investigation of the effect of the light-incidence angle with respect to the substrate plane on the amplitude and sign of the anomalous photovoltage is carried out. According to the previously developed theory, films are investigated in which there is the possibility of providing depleting band bending at the crystallite boundaries, inversion band bending with preservation of the overbarrier current-transport mechanism, and inversion band bending with the current-transport mechanism along the inversion channels. All three types of crystallite boundaries are found in n-PbTe films. It is experimentally established that, for the first and third types of boundaries, a sign inversion of the anomalous photovoltage is observed; for the second type of inversion, it is not observed. The Si films belong to the first type, where only depleting band bending is possible; the sign inversion of the anomalous photovoltage is observed there. The complete agreement between theory and experiment is established. © 2012 Pleiades Publishing, Ltd.


Atakulov S.B.,Fergana State University | Zainolobidinova S.M.,Fergana State University | Nabiev G.A.,Ferghana Polytechnical Institute | Tukhtamatov O.A.,Fergana State University
Semiconductors | Year: 2012

A model for a polycrystalline semiconductor corresponding to its real structure is proposed. On the basis of this model, a mechanism for anomalous photovoltaic effects (the initiation of an anomalous photovoltage, its dependence on illumination angle, and anomalous photomagnetic effect) is developed. It is assumed that potential barriers introducing inhomogeneity into the spatial distribution of photocarriers arise due to the capture of majority charge carriers at surface states of the crystallite boundaries. The effect is heavily dependent on the barrier height: if the band bending at the crystallite boundaries is depleting, the effect is determined by the spatial separation of the majority photocarriers by the barrier; otherwise, (the inversion band bending) the effect is formed due to the separation of minority photocarriers. The basis for the mechanism is the anisotropy of light absorption in the polycrystal's bulk (the depleting band bending) or the geometrical inhomogeneity of the films caused by oblique deposition during fabrication (the inversion band bending.) The cause of the anisotropic absorption of light is its reflection by crystallite boundaries. © 2012 Pleiades Publishing, Ltd.


Abbasov E.S.,Ferghana Polytechnical Institute | Umurzakova M.A.,Ferghana Polytechnical Institute | Nigmatov U.Z.,Ferghana Polytechnical Institute
Applied Solar Energy (English translation of Geliotekhnika) | Year: 2010

Possible ways are shown of intensifying the heat exchange that increases the efficiency of solar water collectors. The efficiency factors for designing highly efficient solar collectors have been obtained. © 2010 Allerton Press, Inc.


Akhmadaliev B.Zh.,Ferghana Polytechnical Institute | Polvonov B.Z.,Ferghana Polytechnical Institute | Yuldashev N.Kh.,Ferghana Polytechnical Institute
Optics and Spectroscopy (English translation of Optika i Spektroskopiya) | Year: 2014

The polariton luminescence spectra of CdTe crystals have been numerically calculated with allowance for the decay of mechanical excitons and compared with the known experimental low-temperature photoluminescence spectra of these crystals. The mechanism of formation of polariton luminescence in dependence of the optical parameters of crystal for the exciton resonance A n=1 is discussed. © 2014 Pleiades Publishing, Ltd.


Ferghana Polytechnical Institute | Entity website

Ozbekiston Respublikasi Prezidentining qarori Muborak Ramazon hayitining manaviy hayotimizda ezgulik, shukronalik, mehr-oqibat kabi olijanob qadriyatlarni qaror toptirishdagi orni va ahamiyatini inobatga olib, milliy-diniy ananalarimizni asrab-avaylash va uluglash maqsadida hamda Ozbekiston Respublikasi Prezidentining Roza hayitini dam olish kuni deb elon qilish togrisidagi 1992-yil 27-martdagi PF-368-son Farmoniga muvofiq: 1. Ozbekiston musulmonlari idorasining 2016-yilda Ramazon hayitining birinchi kuni 6-iyul chorshanba kuniga togri kelishi haqida qabul qilgan qarorini etiborga olib, 2016-yil 6-iyul dam olish kuni deb belgilansin va mamlakatimizda bayram sifatida keng nishonlansin ...


Ferghana Polytechnical Institute | Entity website

O'zbekiston kelajagi uchun yetuk, barkamol va raqobatbardosh kadrlarni tayyorlash!


Ferghana Polytechnical Institute | Entity website

20-22 2016 - ., - ...


Ferghana Polytechnical Institute | Entity website

Qo`mita (bolim) nomi : Hodimlar va talabalar kasaba uyushmasi qo`mitalari. Institutda Hodimlar va talabalar kasaba uyushmasi qo`mitalari Institut jamoa shartnomasi va tarkibiy tuzilishiga asosan tashkil etilgan ...

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