http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Electroluminescence of n-Zn1-xMgxO/ZnO/p-Zn1-xMgxO Heterostructures Grown on Si Substrates
Sh. U. Yuldashev,T. W. Kang,R. A. Nusretov,I. V. Khvan,P. K. Khabibullaev,Y. K. Yeo,R. L. Hengehold 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5
The n-Zn0.9Mg0.1O/ZnO/p-Zn0.9Mg0.1O heterojunction structures were grown on single-crystal p-type Si (100) substrates by using a simple process of ultrasonic spray pyrolysis. Aqueous solutions of zinc acetate, magnesium acetate, and ammonium acetate were used as the sources of Zn, Mg, and N, respectively. P-type conductivity was observed for the nitrogen-doped ZnO and Zn0.9Mg0.1O films. A distinct visible electroluminescence was observed at room temperature from the n-Zn0.9Mg0.1O/ZnO/p-Zn0.9Mg0.1O heterojunction structures under forward bias conditions.
Sh.U. YULDASHEV,Y.D.Woo,임현식,J.K. FURDYNA,이상훈,강태원,X. LIU,Y. SASAKI 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3
We have studied the origin of the resistivity peak which is often observed near the Curie temperature on the resistivity temperature characteristic in Ga1ကxMnxAs epitaxial layers. It was conrmed that the Curie temperature of this ferromagnetic semiconductor is strongly dependent on the concentration of free carriers (holes). The concentration of free holes was controlled by an additional nonmagnetic acceptor (Be) at a xed concentration of magnetic atoms (Mn) of Ga1ကxMnxAs (x = 0.03). We show that the temperature dependences of the resistivity at zero magnetic eld and of the magnetoresistance can be successfully described by the magnetoimpurity scattering model proposed by Nagaev [Phys. Rep. 346, 387 (2001)] in both the paramagnetic and the ferromagnetic temperature regions. Quantitative analysis of the experimental data in terms of this model yields the value of the p-d exchange integral Jpd = 0.07 eV nm3 for Ga0:97Mn0:03As.
Growth of ZnO Nanowires by Electrochemical Deposition into Porous Alumina on Silicon Substrates
Sh.U. Yuldashev,L. A. Nosova,Sung Woo Choi,강태원 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.III
Well-aligned, ZnO nanowire arrays of high density and uniformity were synthesized by electrochemical deposition on silicon substrate using a nanoporous template of anodized aluminum oxide. The high ordered porous alumina layers on silicon substrates were produced by two-step anodization process in oxalic acid . ZnO nanowires were electrodeposited from zinc nitrate-Zn(NO$_3$)$_2$ aqueous solution. The diameter and length of nanowires were controlled by the geometry of the aluminum oxide templates. The structure and optical properties of deposited ZnO nanowires were studied by using SEM and photoluminescence measurements. In PL spectra of as-grown nanowires the green luminescence band at 2.4 eV was dominated. After thermal annealing in ambient atmosphere the bright ultraviolet emission band near the energy gap of ZnO was observed.
Thermal Conductivity of ZnO Single Nanowire
Yuldashev, Sh. U.,Yalishev, V. Sh.,Cho, H. D.,Kang, T. W. American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.2
<P>The thermal conductivity of a single ZnO nanowire with diameter of similar to 150 nm was measured using a four-point-probe 3 omega method over a temperature range of 140-300 K. The measured thermal conductivity of ZnO nanowire is strongly reduced compared to bulk ZnO crystal due to the enhanced phonon-boundary and impurity (isotope) scattering. The maximum of the thermal conductivity is shifted to a higher temperature than that of bulk counterpart. Temperature dependent measurements show that beyond the low-temperature maximum, the thermal conductivity decreases with temperature as T-1.5 indicating strong impurity (isotope) scattering at intermediate and high temperatures.</P>
Critical behavior of the resistivity of GaMnAs near the Curie temperature
Yuldashev, Sh.U.,Yunusov, Z.A.,Kwon, Y.H.,Lee, S.H.,Ahuja, R.,Kang, T.W. Pergamon Press ; Elsevier Science Ltd 2017 Solid state communications Vol.263 No.-
<P>The effect of the magnetization fluctuations on the resistivity of GaMnAs near the Curie temperature T-C was experimentally studied. It is shown that the determination of T-C from the maximum of the temperature derivative of the resistivity is valid for the samples with a high concentration of free carries. Whereas, for the samples with low concentration of free carriers the T-C coincides with the resistivity maximum. The magnetic specific heat for T > T-C demonstrates the crossover from the one dimensional to the three dimensional critical behavior when the temperature become closer to the Curie temperature. This is explained by the formation of the ferromagnetic phase in the paramagnetic side of the phase transition which is started from Mn-Mn dimers oriented along one direction.</P>
Magnetoelectric effect in GaMnAs /P(VDF-TrFE) composite multiferroic nanostructures
Yuldashev, S.U.,Yalishev, V.Sh.,Yunusov, Z.A.,Lee, S.J.,Jeon, H.C.,Kwon, Y.H.,Lee, G.T.,Park, C.M.,Kang, T.W. Elsevier 2015 Current Applied Physics Vol.15 No.suppl2
The electric-field effect on the Curie temperature of the ferromagnetic semiconductor GaMnAs and ferroelectric polyvinylidene fluoride with trifluoroethylene P(VDF-TrFE) multiferroic nanostructures have been investigated. The Curie temperatures of GaMnAs layers were determined from the temperature dependencies of the resistivity at zero magnetic field and the anomalous Hall effect measurements. Under the electric-field potential with different polarities applied to the ferroelectric gate the shift of the Curie temperature in GaMnAs has been observed. The shift of T<SUB>C</SUB> is due to the variation of the hole concentration in the ferromagnetic layer induced by the gate electric field.
Yalishev, Vadim Sh.,Yuldashev, Shavkat U.,Igamberdiev, Khusan T.,Kang, Tae Won,Park, Bae Ho Korean Physical Society 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.1
We studied the photoluminescence (PL) spectra in the near-band-edge region of undoped ZnO films as a function of temperature to determine the thermal quenching behavior in the emission intensity. The quenching of the PL intensity was found to change to an increasing intensity with increasing temperature in the temperature region from 40 to 60 K. On the other hand, a reduction of the vacuum in the same temperature region was observed and was attributed to desorption of oxygen molecules from the cryostat finger. Further investigation revealed that the increase in the PL intensity was caused by adsorption of oxygen on the surface of ZnO films resulting in a decrease in the number of non-radiative recombination centers.