Alpha-Fe2O3 and alpha-Cr2O3 has been mechanical alloyed to prepare Fe1-xCrxO3 oxides for x = 0.2-0.8. Synchrotron X-ray diffraction and Raman spectra have shown inhomogeneous structure of α-Fe2O3 and α-Cr2O3 phases in as-alloyed samples. The as-alloyed samples have shown soft ferromagnetic properties with signature of two Morin transitions. The heat treatment of as-alloyed samples has homogenized structure and successfully incorporated the Cr atoms into the lattice sites of Fe atoms in α-Fe2O3. The magnetic and electrical properties have been modified in the heat treated samples. For example, canted antiferromagnetic order has been appeared as an effect of heat treatment, irrespective of the Cr content in Fe1-xCrxO3. The magnetic field induced spin flop transition has been observed at a critical magnetic field that depends on Cr content in the system. The Mössbauer spectrum at room temperature has been fitted with two sextets. The variation of Mössbauer parameters suggest a distribution of magnetic spin order between Fe and Cr ions in the rhombohedral structure of Fe1-xCrxO3. The electrical conductivity, derived from current-voltage characteristics of the heat treated samples, has been enhanced by increasing Cr content in alpha-Fe2O3 structure. The experimental results have been explained based on the theoretical models available in literature.
We have synthesized Cr1.4Fe0.6O3 compound through mechanical alloying of Cr2O3 and Fe2O3 powders and subsequent thermal annealing. The XRD spectrum, SEM picture and microanalysis of EDAX spectrum have been used to understand the structural evolution in the alloyed compound. The alloyed samples are matching to rhombohedral structure with R3C space group. The observation of a modulated magnetic order confirmed a systematic diffusion of Fe atoms into the Cr sites of lattice structure. A field induced magnetic behaviour is seen in the field dependence of magnetization data of the annealed samples.…
A detailed understanding of the relation between microscopic structure and phonon propagation at the nan oscale is essential to design materials with desired phononic and thermal properties.Here we uncover a new mechanism of phonon interaction in surface oxidized membranes, i.e., native oxide layers interact with phonons in ultra-thin silicon membranes through local resonances. The local resonances reduce the low frequency phonon group velocities and shorten their mean free path. This effect opens up a new strategy for ultralow thermal conductivity design as it complements the scattering mecha…
Monoclinic scheelite bismuth vanadate (BiVO4) is a promising photoanode for water splitting yet the PEC performance is limited due to its relatively higher (2.4 eV) band gap. Here, we successfully decreased its the band gap to 1.72 eV by controlled antimony alloying. Low bandgap antimony alloyed bismuth vanadium oxide (Sb:BiVO4) thin film was prepared by RF sputtering of high purity homemade target, fabricated by solid-state reaction using a mixture of Sb2O3, Bi2O3, and V2O5 powders with desired stoichiometric ratios. Several growth parameters, powder crystallography, post-deposition effects, …
A number of electronic devices involve metal/oxide interfaces in their structure where the oxide layer plays the role of electrical insulator. As the downscaling of devices continues, the oxide thickness can spread over only a few atomic layers, making the role of interfaces prominent on its insulating properties. The prototypical Al/SiO2 metal/oxide interface is investigated using first principle calculations, and the effect of the interfacial atomic bonding is evidenced. It is shown that the interface bonding configuration critically dictates the mechanical and electronic properties of the i…
Many mixed ionic/electronic conductors (MIECs) applied in fuel cell electrodes can be considered as alloys between perovskite oxides and ordered oxygen vacancy compounds. For example, in the model MIEC (STF), low oxygen diffusion barrier exist in SrTiO3 lattice, when it has been mixed with SrFeO2.5 with intrinsic oxygen deficiency, the ionic conductivity can be greatly improved. Meanwhile, the electronic conductivity can be optimized by controlling the defect chemistry of the alloy. However, the configurational space is too large in such alloys so that it is difficult for direct atomic modelin…
High Frequency (GW) Post Processing of Transparent Conductive Oxide, ITO, leads to a significant improvement of Optical Transmission and Electrical Conduction. This is also true in case of ITO films in multilayered structures. The improvements happen without any affecting the lower layers (other layers of the multilayered Device). This Method is extremely selective and can process only the targeted film (layer).
The compound alpha-Fe1.4Ga0.6O3 has been prepared by mechanical alloying of alpha-Fe2O3 and Ga2O3 and subsequent heating of the mechanical alloyed samples in vacuum condition. Magnetic ordering of alpha-Fe2O3 has been modified by substitution of non-magnetic Ga atoms. The ferromagnetism in alpha-Fe1.4Ga0.6O3 is more soft and enhanced in comparison to alpha-Fe2O3. Mössbauer spectroscopy also confirmed enhanced ferromagnetic order in alpha-Fe1.4Ga0.6O3. The room temperature soft ferromagnetism by Ga substitution is interesting for designing alpha-Fe2O3 based unconventional ferromagnet, which is …
This review article aims at illustrating the recent progresses in the electrical control of magnetism in oxides with profound physics and enormous potential applications. In the first part, we provide a comprehensive summary of the electrical control of magnetism in the classic multiferroic heterostructures and clarify their various mechanisms lying behind. The second part focuses on the novel route of electric double layer gating for driving a significantly electronic phase transition in magnetic oxides by a small voltage. The electric field applied on the ordinary dielectric oxide in the thi…
Defect engineering using self-doping or creating vacancies in polycrystalline oxide based materials has profound influence on optical absorption, UV photo detection, and electrical switching. However, defects induced semiconducting oxide devices show enhancement in photo detection and photosensitivity, and hence still remain interesting in the field of optoelectronics. In this study, defect engineering in semiconducting oxide materials is discussed along with their roles in optoelectronic device-based applications. Theoretical investigations have been done for identifying defect states by perf…
In this review, we propose a summary of the most recent advances in the first-principles study of ferroelectric oxide epitaxial thin films and multilayers. We discuss in detail the key roles of mechanical and electrical boundary conditions, providing to the reader the basic background for a simple and intuitive understanding of the evolution of the ferroelectric properties in many nanostructures. Going further we also highlight promising new avenues and future challenges within this exciting field or researches.
The author reports an experimental study of electrical and thermal transport in reduced graphene oxide (RGO)/polystyrene (PS) composites. The electrical conductivity ($σ$) of RGO/PS composites with different RGO concentrations at room temperature shows a percolation behavior with the percolation threshold of ~ 0.25 vol.%. Their temperature-dependent electrical conductivity follows Efros-Shklovskii (ES) variable range hopping (VRH) conduction in the temperature range of 30 to 300 K. The thermal conductivity ($κ$) of composites is enhanced by ~ 90 % as the concentration is increased from 0 to 10…
Surface passivation with acidic (NH4)2S solution is shown to be effective in improving the interfacial and electrical properties of HfO2/GaSb metal oxide semiconductor devices. Compared with control samples, those treated with acidic (NH4)2S solution showed great improvements in frequency dispersion, gate leakage current and interface trap density. These improvements were attributed to the acidic (NH4)2S solution enhancing passivation of the substrates, which was analyzed from the perspective of chemical mechanism and confirmed by X-ray photoelectron spectroscopy and high-resolution cross-sect…
Cuprous (I) oxide (Cu_{2}O) based solar cells were fabricated with the use of the electrodeposition technique at nanometre scale, and the structural, morphological and electrical properties were investigated. The Cu_{2}O layers were electrodeposited on crystalline and polycrystalline copper substrates. To complete the Cu_{2}O/Cu(100) and Cu_{2}O/Cu interfaces as the solar cells the top electrodes of silver paste were painted on the rear of Cu_{2}O. The theoretical analysis of the current voltage curve was provided to determine the values of electrical parameters of the most efficient solar cel…
In this study, we report a different strategy to prepare graphene nanopapers from direct vacuum filtration. Instead of the conventional method, i.e. thermal annealing nanopapers at extremely high temperatures prepared from graphene oxide (GO) or partially reduced GO, we fabricate our graphene nanopapers directly from suspensions of fully reduced graphene oxide (RGO), obtained after RGO and thermally annealing at 1700 °C in vacuum. By using this approach, we studied the effect of thermal annealing on the physical properties of the macroscopic graphene-based papers. Indeed, we demonstrated that …
Current-voltage measurements have been made at room temperature on a Si-rich silicon oxide film deposited via Electron-Cyclotron Resonance Plasma Enhanced Chemical Vapor Deposition (ECR-PECVD) and annealed at 750 - 1000$ ^\circ$C. The thickness of oxide between Si quantum dots embedded in the film increases with the increase of annealing temperature. This leads to the decrease of current density as the annealing temperature is increased. Assuming the Fowler-Nordheim tunneling mechanism in large electric fields, we obtain an effective barrier height $ϕ_{eff}$ of $\sim$ 0.7 $\pm$ 0.1 eV for an e…
We report the results of electrical resistivity measurements carried out on well-sintered La0.7Ca0.3MnO3 / Mn3O4 composite samples with almost constant composition of the magnetoresistive manganite phase (La0.7Ca0.3MnO3). A percolation threshold (fc) occurs when the La0.7Ca0.3MnO3 volume fraction is ~ 0.19. The dependence of the electrical resistivity as a function of La0.7Ca0.3MnO3 volume fraction (fLCMO) can be described by percolation-like phenomenological equations. Fitting the conducting regime (fLCMO > fc) by the percolation power law returns a critical exponent t value of 2.0 +/- 0.2 at…
The paper presents results for zinc oxide films grown at low temperature regime by Atomic Layer Deposition (ALD). We discuss electrical properties of such films and show that low temperature deposition results in oxygen-rich ZnO layers in which free carrier concentration is very low. For optimized ALD process it can reach the level of 10^15 cm-3, while mobility of electrons is between 20 and 50 cm2/Vs. Electrical parameters of ZnO films deposited by ALD at low temperature regime are appropriate for constructing of the ZnO-based p-n and Schottky junctions. We demonstrate that such junctions are…
A giant tunneling electroresistance effect may be achieved in a ferroelectric tunnel junction by exploiting the magnetoelectric effect at the interface between a ferroelectric barrier and magnetic La1-xSrxMnO3 electrode. Using first-principles density functional theory we demonstrate that a few magnetic monolayers of La1-xSrxMnO3 near the interface act, in response to ferroelectric polarization reversal, as an atomic scale spin-valve by filtering spin-dependent current. This effect produces more than an order of magnitude change in conductance, and thus constitutes a giant resistive switching …
We report high temperature synchrotron X-ray diffraction (SXRD), dc magnetization and current-voltage (I-V) characteristics for the samples of Co$_{2.75}$Fe$_{0.25}$O$_4$ ferrite. The material was prepared by chemical reaction of the Fe and Co nitrate solutions at pH = 11 and subsequent annealing at temperatures 200 0C, 500 0C and 900 0C. The measurements were performed by cycling the temperature from 300 K to high temperature (warming mode) and return back to 300 K (cooling mode). The SXRD patterns indicated a fine bi-phased cubic spinel structure in the highly Co rich spinel oxide. Magnetiza…
We determined the interface state density ($D_{\rm it}$) distributions in the vicinity of the conduction band edge in silicon carbide (SiC) metal-oxide-semiconductor (MOS) structures by reproducing the experimental current-voltage characteristics of MOS field effect transistors (MOSFETs) with numerical calculations. In the calculation, potential distributions and energy sub-bands in the inversion layer were calculated by solving Poisson and Schrödinger equations, respectively. We demonstrate that gate characteristics of the MOSFETs are well described by considering that the interface states ar…
Tin doped indium oxide (ITO) thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films in low temperatures (25-300 K). The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kfl~1) and degenerate semiconductor. The transport of charge carriers in these disordered ITO thin films takes place via the de-localized states. The disorder effects lead to the well- known metal-insulator transition; this …
We report the electrical resistivity, thermoelectric power, and thermal conductivity of single-crystalline and sintered samples of the 5d pyrochlore oxide CsW2O6. The electrical resistivity of the single crystal is 3 mohm cm at 295 K and gradually increases with decreasing temperature above 215 K (Phase I). The thermoelectric power of the single-crystalline and sintered samples shows a constant value of approximately -60 uV K-1 in Phase I. These results reflect that the electron conduction by W 5d electrons in Phase I is incoherent and in the hopping regime, although a band gap does not open a…
La-doped SrSnO3 (LSSO) is known as one of deep-ultraviolet (DUV)-transparent conducting oxides with an energy bandgap of ~4.6 eV. Since LSSO can be grown heteroepitaxially on more wide bandgap substrates such as MgO (Eg ~7.8 eV), LSSO is considered to be a good candidate as a DUV-transparent electrode. However, the electrical conductivity of LSSO films are below 1000 S cm^-1, most likely due to the low solubility of La ion in the LSSO lattice. Here we report that high electrically conducting (>3000 S cm^-1) LSSO thin films with an energy bandgap of ~4.6 eV can be fabricated by pulsed laser dep…
Entropy stabilization has garnered significant attention as a new approach to designing novel materials. Much of the work in this area has focused on bulk ceramic processing, leaving entropy-stabilized thin films relatively underexplored. Following an extensive multi-variable investigation of polycrystalline (Mg$_{0.2}$Co$_{0.2}$Ni$_{0.2}$Cu$_{0.2}$Zn$_{0.2}$)O thin films deposited via pulsed laser deposition (PLD), it is shown here that substrate temperature and deposition pressure have strong and repeatable effects on film texture and lattice parameter. Further analysis shows that films depo…
Large Rashba effect efficiently tuned by an external electric field is highly desired for spintronic devices. Using first-principles calculations, we demonstrate that large Rashba splitting is locked at conduction band minimum in ferroelectric Bi(Sc/Y/La/Al/Ga/In)O3/PbTiO3 heterostructures where the position of Fermi level is precisely controlled via its stoichiometry. Fully reversible Rashba spin texture and drastic change of Rashba splitting strength with ferroelectric polarization switching are realized in the symmetric and asymmetric heterostructures, respectively. By artificially tuning t…
The Sn substituted Ni-Zn ferrites were synthesized by the standard double sintering technique using nano powders of nickel oxide (NiO), zinc oxide (ZnO), iron oxide (Fe2O3) and tin oxide (SnO2). The structural and electrical properties have been investigated by the X-ray diffraction, scanning electron microscopy, DC resistivity and dielectric measurements. Extra intermediate phase has been detected along with the inverse cubic spinel phase of Ni-Zn ferrite. Enhancement of grain size is observed in Sn substituted Ni-Zn ferrites. DC resistivity as a function of temperature has been investigated …
Lanthanum manganite, LaMnO (LMO) is the parent compound for a class of hole doped(e.g. La1-xCaxMnO3, La1-xSrxMnO3) and electron doped (e.g. . La1-xCexMnO3, La1-xSnxMnO3) perovskite complex oxide materials. Strong correlation between the spin,lattice, charge and orbital degrees of freedom is a hallmark of these class of materials (popularly known as manganites). Competition and interplay of these degrees of freedom lead to a wide range of interesting electronic behavior including half-metallicity, colossal magneto-resistivity, etc. Although a lot of experimental research has been carried out on…
A compound with metallic electrical conductivity usually has a considerable total thermal conductivity because both electrons and photons contribute to thermal transport. Here, we show an exceptional example of iridium oxide, Bi3Ir3O11, that concurrently displays metallic electrical conductivity and ultralow thermal conductivity approaching 0.61 W m-1 K-1 at 300 K. The compound crystallizes into a cubic structural framework with space group Pn-3. The edge- and corner-sharing IrO6 octahedra with a mixed Ir4.33+ charge state favor metallic electrical transport. Bi3Ir3O11 exhibits an extremely lo…
Combination of electrical conductivity and optical transparency in the same material -- known to be a prerogative of only a few oxides of post-transition metals, such as In, Sn, Zn and Cd -- manifests itself in a distinctive band structure of the transparent conductor host. While the oxides of other elements with $s^2$ electronic configuration, for example, Mg, Ca, Sc and Al, also exhibit the desired optical and electronic features, they have not been considered as candidates for achieving good electrical conductivity because of the challenges of efficient carrier generation in these wide-band…
Epitaxial thin films of the substitutionally alloyed half-Heusler series CoTi$_{1-x}$Fe$_x$Sb were grown by molecular beam epitaxy on InAlAs/InP(001) substrates for concentrations 0.0$\leq$x$\leq$1.0. The influence of Fe on the structural, electronic, and magnetic properties was studied and compared to that expected from density functional theory. The films are epitaxial and single crystalline, as measured by reflection high-energy electron diffraction and X-ray diffraction. Using in-situ X-ray photoelectron spectroscopy, only small changes in the valence band are detected for x$\leq$0.5. For …
Electrical and optical properties of amorphous vanadium oxide thin films obtained by electrochemical anodic oxidation are studied. It is shown that under cathodic polarization the hydrogen insertion into vanadium oxide from an electrolyte occurs. Metal-insulator transition in amorphous HxVO2 is found to be preserved up to high concentration (x ~ 1.5) of hydrogen. Memory switching with the N-type negative differential resistance, associated with the H+ ionic transfer, is observed in "V/hydrated amorphous vanadium oxide/Au" sandwich structures.
We have used the classical Hall effect to electrically characterize Indium Tin Oxide (ITO) films grown by two different techniques on silica substrates. ITO films have the unique property that they can be both electrically conducting (and to be used for a gate electrode for example) as well as optically transparent (at least in the visible part of the spectrum). In the near infrared (NIR) the transmission typically reduces. However, the light absorption can in principle be compensated by growing thinner films.
The conductive domain wall (CDW) is extensively investigated in ferroelectrics, which can be considered as a quasi-two-dimensional reconfigurable conducting channel embedded into an insulating material. Therefore, it is highly important for the application of ferroelectric nanoelectronics. Hitherto, most CDW investigations are restricted in oxides, and limited work has been reported in non-oxides to the contrary. Here, by successfully synthesizing the non-oxide ferroelectric Sn2P2S6 single crystal, we observed and confirmed the domain wall conductivity by using different scanning probe techniq…
The impedance behavior of pre-oxidized iron in liquid lead-bismuth eutectic (LBE) at 200 oC is studied using electrochemical impedance spectroscopy. The structures and resistance of oxide grown on iron oxidized in air at different temperatures and durations are compared. The results show that the resistance of the oxide film increases with increasing oxidizing temperature, due to the formation of a thicker scale and fewer defects. At the same temperature (600 oC), increasing the oxidation time can also reduce the defect concentration in the oxide film and improve the impedance of the oxide sca…
An electrical study of thin $VO_{2}$ films in the vicinity of the structural phase transition at $68^{0}C$ shows (a) that the electrical resistance $R$ follows $log (R)$ $\propto$ $-T$ over the $T$-range, $20 < T < 80 ^{0}C$ covering both sides of the structural transition, and (b) a history dependent hysteresis loop in $R$ upon thermal cycling. These features are attributed here to transport through a granular network.
The use of oxide glasses is pervasive throughout everyday amenities and commodities. Such glasses are typically electrical insulators, and endowing them with electrical conductivity without changing their salutary mechanical properties, weight, or thermoformability enables new applications in multifunctional utensils, smart windows, and automotive parts. Previous strategies to impart electrical conductivity include modifying the glass composition or forming a solid-in-solid composite of the glass and a conductive phase. Here we demonstrate using the latter strategy the highest reported room-te…
Towards next-generation spintronics devices, such as computer memories and logic chips, it is necessary to satisfy high thermal stability, low-power consumption and high spin-polarization simultaneously. Here, from first-principles, we investigate thermal stability (both structure and magnetization) and the electric field control of magnetic anisotropy on Co2FeAl (CFA)/MgO. A phase diagram of structural thermal stability of the CFA/MgO interface is illustrated. An interfacial perpendicular-anisotropy, coming from the Fe-O orbital hybridization, provides high magnetic thermal stability and a lo…
Broadband Dielectric Spectroscopy (BDS) measurements of Pοlyaniline/Graphene oxide composites were conducted for an as-prepared and a thermally annealed specimen, respectively, from 15K to room temperature. Electrical conductivity values of the annealed composite display a very modest rise denoting the important contributions of the GO component to achieving electrical stability of the polymer. Patterns of the dc conductivity as a function of temperature also reveal a metal to insulator transition around 75K. The transition is dominated by two key factors; temperature and annealing process. Me…
The structural, optical and electrical properties of spray deposited antimony (Sb) doped tin oxide (SnO2) thin films, prepared from SnCl4 precursor, have been studied as a function of antimony doping concentration. The doping concentration was varied from 0 to 1.5 wt.% of Sb. The analysis of x-ray diffraction patterns revealed that the as deposited doped and undoped tin oxide thin films are pure crystalline tetragonal rutile phase of tin oxide which belongs to the space group P42/mnm (number 136). The surface morphological examination with field emission scanning electron microscopy (FESEM) re…
Electrically detected magnetic resonance is used to identify recombination centers in a set of Czochralski grown silicon samples processed to contain strained oxide precipitates with a wide range of densities (~ 1e9 cm-3 to ~ 7e10 cm-3). Measurements reveal that photo-excited charge carriers recombine through Pb0 and Pb1 dangling bonds and comparison to precipitate-free material indicates that these are present at both the sample surface and the oxide precipitates. The electronic recombination rates vary approximately linearly with precipitate density. Additional resonance lines arising from i…
Transparent conducting oxides (TCOs) play an essential role in modern optoelectronic devices through their combination of electrical conductivity and optical transparency. We review recent progress in our understanding of multi-component TCOs formed from solid-solutions of ZnO, In2O3, Ga2O3 and Al2O3, with a particular emphasis on the contributions of materials modelling, primarily based on Density Functional Theory. In particular, we highlight three major results from our work: (i) the fundamental principles governing the crystal structures of multi-component oxide structures including (In2O3…
The micro-properties (structure and composition), and macro-properties (electrical and optical properties) of zinc oxide (ZnO) thin films deposited on glass substrates using a filtere vacuum arc deposition (FVAD) system were investigated as a function of oxygen pressure (0.37 - 0.5 Pa) and arc current (100 - 300 A). Correlations between the various properties were investigated.
Developing materials that can lead to compact versions of artificial neurons (neuristors) and synapses (memristors) is the main aspiration of the nascent neuromorphic materials research field. Oscillating circuits are interesting as neuristors, emulating the firing of action potentials. We present room-temperature self-oscillating devices fabricated from epitaxial thin films of semiconducting TbMnO3. We show that these electrical oscillations induce concomitant mechanical oscillations that produce audible sound waves, offering an additional degree of freedom to interface with other devices. Th…
The inherent network of nanopores and voids in silicon dioxide (SiO2) is generally undesirable for aspects of film quality, electrical insulation and dielectric performance. However, if we view these pores as natural nano-patterns embedded in a dielectric matrix then that opens up new vistas for exploration. The nano-pattern platform can be used to tailor electrical, optical, magnetic and mechanical properties of the carrier film. In this article we report the tunable electrical properties of thermal SiO2 thin-film achieved through utilization of the metal-nanopore network where the pores are …
The present approach to SERS does not rely on a hihj electrical conductivity substrate or admixture to enable the SERS process. The novelty of our method is to create an artificial periodic electron distribution on a surface by illumination with ultraviolet radiation whose photon energy is above the photoelectric work function of the material.
The dielectric breakdown (BD) of thermal oxide (SiO2) grown on cubic silicon carbide (3C-SiC) was investigated comparing the electrical behavior of macroscopic metal-oxidesemiconductor (MOS) capacitors with nanoscale current and capacitance mapping using conductive atomic force (C-AFM) and scanning capacitance microscopy (SCM). Spatially resolved statistics of the oxide BD events by C-AFM revealed that the extrinsic premature BD is correlated to the presence of peculiar extended defects, the anti-phase boundaries (APBs), in the 3C-SiC layer. SCM analyses showed a larger carrier density at the …
Ionic layer epitaxy (ILE) has recently been developed as an effective strategy to synthesize nanometer-thick 2D materials with a non-layered crystal structure, such as ZnO. The packing density of the amphiphilic monolayer is believed to be a key parameter that controls the nanosheet nucleation and growth. In this work, we systematically investigated the growth behavior of single-crystalline ZnO nanosheets templated at the water-air interface by an anionic oleylsulfate monolayer with different packing densities. The thicknesses of ZnO nanosheets were tuned from one unit cell to four unit cells,…
Optimized DC magnetron sputtering system for the deposition of transparent conductive oxides (TCOs), such indium tin oxide (ITO) on glass substrate has been applied in order to achieve low-emitting (low-e) transparent coatings. To obtain the concerned electrical resistance and high infrared reflection, first the effect of applied sputtering power then oxygen flow on the properties of films have been investigated. The other depositions parameters are kept constant. Film deposition at at temperature 400 degree of Celsius in oxygen flow of 3 Standard Cubic Centimeters per Minute results in transp…
Flexible fully transparent diodes with high rectification ratio of 5 e 8 are fabricated with all oxide materials at low temperature. The devices are optically transparent in visible spectra range and electrically robust while mechanically bending. Distinguished from other diodes, these diodes utilize diode-connected thin-film transistor architecture and follow field-effect principles.
The problem of detecting the ability of some metal oxides as photocatalysts is receiving considerable attention in the world. The studied zinc oxide is considered as one of the most utilized semiconductors, due to its direct band gap of 3.37 eV and a large exciton binding energy of 60 meV at room temperature. The characteristic formulation of Copper doped zinc oxide is implemented to obtain an improved adsorption kinetics and photocatalytic activity of zinc oxide photocatalyst capable of evolving estimated photoluminescence (PL) spectra of zinc oxide nanoparticles to explore the effect of Copp…
We report a chemical free method for the reduction of graphene oxide (GO) thin films. It was observed how for GO films annealed in air the oxygen species desorb from the GO surface upon exposure to UV light and how the surface resistivity of such deoxygenated GO films decreases with increasing the exposure to the UV light. The obtained results open a clean as well as easy route for the integration of GO based materials into optoelectronic devices.
Single Crystalline Fe3-deltaO4 (0<=delta<=0.33) films have been epitaxially grown on InAs (001) substrates by molecular beam epitaxy using O2 as source of active oxygen. Under optimum growth conditions in-situ real time reflection high-energy electron diffraction patterns along with ex-situ atomic force microscopy indicated the (001) Fe3-deltaO4 to be grown under step-flow-growth mode with a characteristic surface reconstruction. X-ray photoelectron spectroscopy demonstrate the possibility to obtain iron oxides with compositions ranging from Fe3O4 to gamma-Fe2O3. Superconducting quantum interf…
We have successfully demonstrated Si/GaAs p-n heterostructures using Al2O3 ultra-thin oxide interfacial layers. The band diagram and band offsets were investigated using X-ray photoelectron spectroscopy and confirm a small discontinuity in the conduction band (0.03 eV) at the interface. The interface defect density (Dit) values of the heterointerface with different ultra-thin oxide (UO) thicknesses ranged from 0.35 nm to 3.5 nm and were also characterized based on a metal-oxide-semiconductor capacitor (MOSCAP) structure using a capacitance-voltage measurement. The results revealed that a thin …
Silicon oxide (SiOx) has been widely used in many electronic systems as a supportive and insulating medium. Here we demonstrate various electrical phenomena such as negative differential resistance, resistive switching and current hysteresis intrinsic to a thin layer of SiOx. These behaviors can largely mimic numerous electrical phenomena observed in molecules and other nanomaterials, suggesting that substantial caution should be paid when studying conduction in electronic systems with SiOx as a component. The actual switching can be the result of SiOx and not the presumed molecular or nanomat…
Transparent electronic materials are increasingly in demand for a variety of optoelectronic applications. BaSnO3 is a semiconducting oxide with a large band gap of more than 3.1 eV. Recently, we discovered that La doped BaSnO3 exhibits unusually high electrical mobility of 320 cm^2(Vs)^-1 at room temperature and superior thermal stability at high temperatures [H. J. Kim et al. Appl. Phys. Express. 5, 061102 (2012)]. Following that work, we report various physical properties of (Ba,La)SnO3 single crystals and films including temperature-dependent transport and phonon properties, optical propert…
