Fabrication and study of the organic-inorganic semiconductor diodes formed on n-Si

We report fabrication and electrical characterization of the organic-inorganic semiconductor diode structures formed by evaporating thin films of three novel low molecular mass organic compounds on n-type Si substrates. The organic compounds containing carbazole and triphenylamine structural units, namely: 9,9'-bis(4-butylphenyl)-3,3'-bicarbazolyl (BPBC), 4-(1H-perimidin-2-yl)-N,N-diphenylbenzenamine (PER) and 9,9'-diethyl-3,3'-bicarbazolyl (EBC) have been synthesized. The current-voltage characteristics of the Au/(BPBC, EBC, PER)/n-Si diode structures measured at T = 295 K revealed rectifying behavior with a potential barrier height values of 0.71 eV, 0.73 eV, 0.76 eV, respectively

Growth and investigation of oxide heterostructures based on half-metallic Fe3O4

We report thin films of ferromagnetic Fe3O4 (magnetite) grown by a reactive magnetron sputtering at T=300÷450°C on lattice-matched MgO, and bilayer structures composed of Fe3O4 and underlying epitaxial films of highly conductive electron-doped In2O3 , LaNiO3 , and antiferromagnetic CoO. The prepared Fe3O4 /MgO films and the bilayer structures demonstrated clearly defined resistance anomaly at Verwey transition point (T V ~100-120K). Formation of high resistance interlayer was indicated between the adjacent conducting Fe3O4 and LaNiO 3 layers. However, relatively low interface resistivity of about 0.1Ωcm 2 (at T=300K) was estimated for the patterned Fe3O4 /In2O3 bilayer structures. Vertical electrical transport measurements revealed strong nonlinearity in the I-U dependences of the Fe3O4 /In2O3 interface at T<T V

Investigation of Optically Modified YBa2Cu3O7–x Films by Means of X-ray Microanalysis Technique

<p>This work reports on investigation of remnant oxygen content in optically-modified regions of 0.3-mm-thick YBa₂Cu₃O_{7–<em>x</em>} films, patterned by a laser-writing technique in an inert ambient gas atmosphere at room temperature. A laser-treated region of weak superconductivity with dimensions depending on the size of a laser spot, laser power, and initial content of oxygen is characterized by a lower oxygen content, weaker critical magnetic field, and suppressed both the superconducting critical temperature and the critical current density, as compared to the laser untreated regions. Optically induced (cw-laser, <br /> 532-nm-wavelength) heating strongly affects a non-uniform distribution of remnant oxygen content in the film, depending both on the optical power and beam’s scanning velocity. A level of oxygen depletion and the size of the oxygen-deficient region have been directly estimated from scanning-electron-microscope spectra with the X-ray microanalysis technique. The results of our measurements were compared with results extracted from electric measurements, assuming a correlation between the remnant oxygen content and the electric transport properties of oxygen-deficient YBa₂Cu₃O_{7–<em>x</em>} films.</p> <p>DOI: <a href="http://dx.doi.org/10.5755/j01.ms.20.2.6323">http://dx.doi.org/10.5755/j01.ms.20.2.6323</a></p

Influence of preparation conditions on electrical properties of the Al/Alq3/Si diode structures

Hybrid organic-inorganic diode structures, Al/Alq3/n-Si and Al/Alq3/p-Si based on thin films of tris(8-hydroxyquinoline) aluminum (Alq3) have been investigated. The Alq3 films were evaporated in vacuum and spin coated onto patterned areas of crystalline n- and p-type Si substrates with chemically removed native SiO2 layer. Current-voltage characteristics of the diode structures demonstrated improved rectification property compared to similar Al/n-Si and Al/p-Si device structures. Increased barrier height values (0.90 eV ÷ 1.1 eV and 0.77 eV ÷ 0.91 eV for the Al/Alq3/n-Si and Al/Alq3/p-Si device structures, respectively) certified presence of an interface dipole induced by the organic interlayer. Non-ideal behavior of forward current-voltage characteristics has been explained assuming non-uniformity of barrier height, presence of interface states, and influence of the organic film on diode series resistance and space charge limited current

Fabrication and Study of the Organic-Inorganic Semiconductor Diodes Formed on n-Si

We report fabrication and electrical characterization of the organic-inorganic semiconductor diode structures formed by evaporating thin films of three novel low molecular mass organic compounds on n-type Si substrates. The organic compounds containing carbazole and triphenylamine structural units, namely: 9,9'-bis(4-butylphenyl)-3,3'-bicarbazolyl (BPBC), 4-(1H-perimidin-2-yl)-N,N-diphenylbenzenamine (PER) and 9,9'-diethyl-3,3'-bicarbazolyl (EBC) have been synthesized. The current-voltage characteristics of the Au/(BPBC, EBC, PER)/n-Si diode structures measured at T = 295 K revealed rectifying behavior with a potential barrier height values of 0.71 eV, 0.73 eV, 0.76 eV, respectively

Investigation of Heterostructure Formed from Hole- and Electron-Doped Lanthanum Manganites

High crystalline quality films of n-La2/3Ce1/3MnO3, p-La2/3Ca1/3MnO3 and related p-n diode structures were grown heteroepitaxially on lattice-matched SrTiO3(100) substrates by dc magnetron sputtering and pulsed laser deposition. The La2/3Ce1/3Mn O3/La2/3Ca1/3MnO3 bilayer was patterned into a strip-like geometry to investigate electrical properties of the interface. Significant magnetoresistance values and nonlinear current-voltage characteristics were indicated for the interface of the p-n diode heterostructure

Microwave detection properties of asymmetrically narrowed YBa2Cu3O7–x structures

Results of our research demonstrate possibilities of detection of microwaves radiation by means of asymmetrically narrowed YBa2Cu3O7-x oxygen-rich (x ≤ 0.2) and oxygen-decomposed (x > 0.5) in the necked region at temperatures higher than the critical temperature of the superconductor Tc at which superconductor exhibits properties of a heavily-doped semiconductor. Both types of structures, mounted into a 10 GHz waveguide, generate sub-linearly increasing amplitude of detected voltage with increase of incident power of pulsed 10-GHz-frequency microwave radiation. The voltage sensitivity Sx ≤ 0.2 ≥ 1.3 mV/W of oxygen-rich and Sx > 0.5 ≥ 9 mV/W of oxygen-decomposed structure were measured at room temperature. Asymmetrical shape of nonlinear current-voltage dependences depends on oxygen content x in the necked region and temperature of the tested structure. Our results show that the asymmetrically narrowed structure with a necked region down to 10 μmm made of partially deoxygenated YBa2Cu3O7–x superconductor can be used as a nonsuperconducting, nonlinear on-chip element (detector of MW power) in the YBa2Cu3O7–x chip operating at temperatures below critical temperature Tc of the chip superconductor

Investigation of heterostructure formed from hole- and electron-doped lanthanum manganites

High crystalline quality films of n-La2/3Ce1/3MnO3, p-La2/3Ca1/3MnO3 and related p-n diode structures were grown heteroepitaxially on lattice-matched SrTiO3(100) substrates by dc magnetron sputtering and pulsed laser deposition. The La2/3Ce1/3Mn O3/La2/3Ca1/3MnO3 bilayer was patterned into a strip-like geometry to investigate electrical properties of the interface. Significant magnetoresistance values and nonlinear current-voltage characteristics were indicated for the interface of the p-n diode heterostructure