The nature and concentration of defects near niobium-silicon interfaces prepared with different silicon surface treatments were characterized using current-voltage (I-V), deep level transient spectroscopy (DLTS), and secondary ion mass spectroscopy (SIMS). All samples have H, C, O, F, and Cl chemical contamination in the Si within 50 nm of the interface and electrically active defects with activation energies of 0.147, 0.247, 0.339, and 0.556 eV above the valence band maximum (E$_{vbm}$). In all cases, the deep level defect concentration is dominated by the hole trap at E$_{vbm}$ + 0.556eV, which we assign to a Nb point defect in Si, presumably Nb$_\textrm{Si}$. This defect is present with concentrations ranging from $7\times10^{13}$ to $5\times10^{14}$ cm$^{-3}$ and depends on the final surface clean process.
The optimum surface treatment used in this study is an HF etch followed by an in-situ 100 eV Ar-gas ion milling process. Higher energy ion milling is found to increase the electrically active Nb defect concentration in the Si, and increase the concentration of defects. The HF etch alone removes O from the interface, but results in significant H and F contamination, electrically-active point defect concentrations, and levels of Shockley-Reed-Hall recombination (i.e. Nb/Si Schottky diodes with an ideality factor, n, of $\approx$ 1.6). The RCA clean increases the depth and concentration of H, F, C, and Nb contamination.
Flexible NbC nanocomposite thin films with carbon content ranging from 0 to 99 at.% were deposited at room temperature on Si (100) and polystyrene substrates by non-reactive magnetron sputtering from pure Nb and C targets without applying bias voltage to the substrates. HRTEM images reveal that the films exhibit a nanocomposite structure consisting of NbC nanocrystals (2 to 15 nm in size) embedded in an amorphous carbon matrix. By simply adjusting the Nb flux in the plasma, we can monitor the nanocrystal size and the percent of free-carbon phase in the films, which in turn allows for the tailo…
The new high strength high electrical conductivity materials are demanded for advanced electric applications. Among them Cu-Ag and Cu-Nb wires are promising materials for generators of strong and variable magnetic fields production. Review of selected results of the studies into Cu-Ag and Cu-Nb based composite materials shows presence of various, not always well explained, mechanisms and phenomena which are observed during their production, examination and applications. Two classical copper alloys (with silver and with niobium) were selected for the investigations. The third material used in t…
We report on the electrical characterisation of a series of thin chromium oxide films, grown by dc sputtering, to evaluate their suitability for use as on-chip resistors in nanoelectronics. By increasing the level of oxygen doping, the room-temperature sheet resistance of the chromium oxide films was varied from 28$Ω/ \square$ to 32.6k$Ω/ \square$. The variation in resistance with cooling to 4.2K in liquid helium was investigated; the sheet resistance at 4.2K varied with composition from 65$Ω/ \square$ to above 20G$Ω/ \square$. All of the films measured displayed ohmic behaviour at all measure…
Pulsed electrically-detected magnetic resonance of phosphorous (31P) in bulk crystalline silicon at very high magnetic fields (B > 8.5 T) and low temperatures (T = 2.8 K) is presented. We find that the spin-dependent capture and reemission of highly polarized (>95%) conduction electrons by equally highly polarized 31P donor electrons introduces less decoherence than other mechanisms for spin-to-charge conversion. This allows the electrical detection of spin coherence times in excess of 100 microseconds: 50 times longer than the previous maximum for electrically-detected spin readout experiment…
Electrically detected magnetic resonance (EDMR) is applied to mm size devices with implanted leads and a 50 micron square gap laid down on bulk phosphorus doped silicon. Devices with a range of phosphorus concentrations and surface types were prepared and measured to examine the interplay between donor and charge trap states in producing EDMR signals.
We demonstrate the electrical detection of pulsed X-band Electron Nuclear Double Resonance (ENDOR) in phosphorus-doped silicon at 5\,K. A pulse sequence analogous to Davies ENDOR in conventional electron spin resonance is used to measure the nuclear spin transition frequencies of the $^{31}$P nuclear spins, where the $^{31}$P electron spins are detected electrically via spin-dependent transitions through Si/SiO$_2$ interface states, thus not relying on a polarization of the electron spin system. In addition, the electrical detection of coherent nuclear spin oscillations is shown, demonstrating…
The electrical conductance of porous silicon fabricated with heavily doped p-type silicon is very sensitive to NO$_2$. A concentration of 10 ppb can be detected by monitoring the current injection at fixed voltage. However, we show that the sign of the injection variations depends on the porous layer thickness. If the thickness is sufficiently low -- of the order of few \micro\meter{} -- the injection decreases instead of increasing. We discuss the effect in terms of an already proposed twofold action of NO$_2$, according to which the free carrier density increases, and simultaneously the ener…
We demonstrate that the spin of optically addressable point defects can be coherently driven with AC electric fields. Based on magnetic-dipole forbidden spin transitions, this scheme enables spatially confined spin control, the imaging of high-frequency electric fields, and the characterization of defect spin multiplicity. While we control defects in SiC, these methods apply to spin systems in many semiconductors, including the nitrogen-vacancy center in diamond. Electrically driven spin resonance offers a viable route towards scalable quantum control of electron spins in a dense array.
We have performed continuous wave and pulsed electron spin resonance measurements of implanted bismuth donors in isotopically enriched silicon-28. Donors are electrically activated via thermal annealing with minimal diffusion. Damage from bismuth ion implantation is repaired during thermal annealing as evidenced by narrow spin resonance linewidths (B_pp=12uT and long spin coherence times T_2=0.7ms, at temperature T=8K). The results qualify ion implanted bismuth as a promising candidate for spin qubit integration in silicon.
Ductile Regime Machining of semiconductors (DRM) offers higher quality of the resulting surfaces. To optimize this process, it is required to understand the thermal kinetics of silicon metallization under pressure. Such understanding is not yet possible since the metallic phases of silicon aren't readily amenable to thermal characterization through direct measurements. This being the case, one has to rely on processing indirect measurement data to deduce refined estimates of the thermal transport properties of pressurized Silicon. A feasible measurement of this sort is the electrical resistivi…
The electron spins of semiconductor defects can have complex interactions with their host, particularly in polar materials like SiC where electrical and mechanical variables are intertwined. By combining pulsed spin resonance with ab-initio simulations, we show that spin-spin interactions within SiC neutral divacancies give rise to spin states with an enhanced Stark effect, sub-10**-6 strain sensitivity, and highly spin-dependent photoluminescence with intensity contrasts of 15-36%. These results establish SiC color centers as compelling systems for sensing nanoscale fields.
We investigate the structural, electronic, mechanical and elastic properties of two niobium based intermetallic compounds Nb3Be and Nb3Be2 by using the DFT based theoretical method. A good agreement is found among the structural parameters of both the phases with experimentally evaluated parameters. For both the phases metallic conductivity is observed while Nb3Be phase is more conducting than that of Nb3Be2 phase. Evaluated DOS at Fermi level indicates that Nb3Be2 phase is electrically more stable than Nb3Be phase. For both phases Nb-4d states is mostly responsible for metallic conductivity. …
When the sulfur element is hyperdoped into crystalline silicon to a supersaturated density of 1020 cm-3, it can enhance the sub-bandgap light absorption of silicon from 0 to 70%, with the antireflection of surface dome structures. On the other hand, the local Si: S configuration that can contribute to the strong sub-bandgap absorption is still unknown. In order to find more characteristics of this local Si:S configuration, we thermally annealed the textured sulfur hyperdoped silicon, and analyzed the changes of its optical and electrical properties. We find that the imaginary part of the compl…
Electrically driven emission from negatively charged silicon-vacancy, (SiV)- centres in single crystal diamond is demonstrated. The SiV centres were generated using ion implantation into an intrinsic (i) region of a p-i-n single crystal diamond diode. Both electroluminescence and the photoluminescence signals exhibit the typical emission that is attributed to the (SiV)- centres. Under forward and reversed biased PL measurements, no signal from the neutral (SiV)0 defect could be observed. The realization of electrically driven (SiV)- emission is promising for scalable nanophotonics devices empl…
A wide range of electrochemical reactions of practical importance occur at the interface between a semiconductor and an electrolyte. We present an embedded density-functional theory method using the recently released self-consistent continuum solvation (SCCS) approach to study these interfaces. In this model, a quantum description of the surface is incorporated into a continuum representation of the bending of the bands within the electrode. The model is applied to understand the electrical response of silicon electrodes in solution, providing microscopic insights into the low-voltage region, …
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…
High stress stoichiometric silicon nitride resonators, whose quality factors exceed one million, have shown promise for applications in sensing and signal processing. Yet, electrical integration of the insulating silicon nitride resonators has been challenging, as depositing even a thin layer of metal degrades the quality factor significantly. In this work, we show that graphene used as a conductive coating for Si3N4 membranes reduces the quality factor by less than 30 % on average, which is minimal when compared to the effect of conventional metallization layers such as chromium or aluminum. …
We investigate the spin species relevant for the spin-dependent recombination used for the electrical readout of coherent spin manipulation in phosphorus-doped silicon. Via a multi-frequency pump-probe experiment in pulsed electrically detected magnetic resonance, we demonstrate that the dominant spin-dependent recombination transition occurs between phosphorus donors and Si/SiO2 interface states. Combining pulses at different microwave frequencies allows us to selectively address the two spin subsystems participating in the recombination process and to coherently manipulate and detect the rel…
We demonstrate radio frequency (RF) readout of electrically detected magnetic resonance in phosphorus-doped silicon metal-oxide field-effecttransistors (MOSFETs), operated at liquid helium temperatures. For the first time, the Si:P hyperfine lines have been observed using radio frequency reflectometry, which is promising for high-bandwidth operation and possibly time-resolved detection of spin resonance in donor-based semiconductor devices. Here we present the effect of microwave (MW) power and MOSFET biasing conditions on the EDMR signals.
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 …
Paramagnetic centers in a solid-state environment usually give rise to inhomogenously broadened electron paramagnetic resonance (EPR) lines, making conventionally detected free induction decay (FID) signals disappear within the spectrometer dead time. Here, experimental results of an electrically detected FID of phosphorus donors in silicon epilayers with natural isotope composition are presented, showing Ramsey fringes within the first 150 ns. An analytical model is developed to account for the data obtained as well as for the results of analogous two-pulse echo experiments. The results of a …
We present an ab initio calculation of the DC conductivity of amorphous silicon and hydrogenated amorphous silicon. The Kubo-Greenwood formula is used to obtain the DC conductivity, by thermal averaging over extended dynamical simulation. Its application to disordered solids is discussed. The conductivity is computed for a wide range of temperatures and doping is explored in a naive way by shifting the Fermi level. We observed the Meyer-Neldel rule for the electrical conductivity with E_MNR = 0.06 eV and a temperature coefficient of resistance, TCR ~ -2.0% K^-1 for a-Si:H. In general, experime…
We use electrical spin injection to probe exchange interactions in phosphorus doped silicon (Si:P). The detection is enabled by a magnetoresistance effect that demonstrates the efficiency of exchange in imprinting spin information from the magnetic lead onto the localized moments in the Si:P region. A unique Lorentzian-shaped signal existing only at low temperatures ($\lesssim 25 K$) is observed experimentally and analyzed theoretically in electrical Hanle effect measurement. It stems from spin-dependent scattering of electrons by neutral impurities in Si:P. The shape of this signal is not dir…
Colour centres with long-lived spins are established platforms for quantum sensing and quantum information applications. Colour centres exist in different charge states, each of them with distinct optical and spin properties. Application to quantum technology requires the capability to access and stabilize charge states for each specific task. Here, we investigate charge state manipulation of individual silicon vacancies in silicon carbide, a system which has recently shown a unique combination of long spin coherence time and ultrastable spin-selective optical transitions. In particular, we de…
We report electrically detected magnetic resonance of phosphorus donors in a silicon field-effect transistor. An on-chip transmission line is used to generate the oscillating magnetic field allowing broadband operation. At milli-kelvin temperatures, continuous wave spectra were obtained up to 40 GHz, using both magnetic field and microwave frequency modulation. The spectra reveal the hyperfine-split electron spin resonances characteristic for Si:P and a central feature which displays the fingerprint of spin-spin scattering in the two-dimensional electron gas.
We observed spin injection into silicon through Fe/MgO tunnel barrier by using non-local magnetoresistance measurement technique. Fe/MgO tunnel barrier contacts with a lateral spin valve structure were fabricated on phosphorous doped silicon-on-insulator substrate. Spin injection signals in the non-local scheme were observed up to 120K, which is the highest value where band transferred spins in Si have ever been reported, and spin diffusion length was estimated to be about 2.25um at 8K. Temperature dependence and injection current dependence of the non-local voltage were also investigated. It …
Interfacing solid-state defect electron spins to other quantum systems is an ongoing challenge. The ground-state spin's weak coupling to its environment bestows excellent coherence properties, but also limits desired drive fields. The excited-state orbitals of these electrons, however, can exhibit stronger coupling to phononic and electric fields. Here, we demonstrate electrically driven coherent quantum interference in the optical transition of single, basally oriented divacancies in commercially available 4H silicon carbide. By applying microwave frequency electric fields, we coherently driv…
We demonstrate electrical injection and detection of spin-polarized electrons in silicon (Si) using epitaxially grown Fe_3Si/Si Schottky-tunnel-barrier contacts. By an insertion of a delta-doped n^+-Si layer (~ 10^19 cm^-3) near the interface between a ferromagnetic Fe_3Si/Si contact and a Si channel (~ 10^15 cm^-3), we achieve a marked enhancement in the tunnel conductance for reverse-bias characteristics of the Fe_3Si/Si Schottky diodes. Using laterally fabricated four-probe geometries with the modified Fe_3Si/Si contacts, we detect nonlocal output signals which originate from the spin accum…
We implanted ultra low doses (2x10^11 cm-2) of 121Sb ions into isotopically enriched 28Si and find high degrees of electrical activation and low levels of dopant diffusion after rapid thermal annealing. Pulsed Electron Spin Resonance shows that spin echo decay is sensitive to the dopant depths, and the interface quality. At 5.2 K, a spin decoherence time, T2, of 0.3 ms is found for profiles peaking 50 nm below a Si/SiO2 interface, increasing to 0.75 ms when the surface is passivated with hydrogen. These measurements provide benchmark data for the development of devices in which quantum informa…
Neutrally charged divacancies in silicon carbide (SiC) are paramagnetic color centers whose long coherence times and near-telecom operating wavelengths make them promising for scalable quantum communication technologies compatible with existing fiber optic networks. However, local strain inhomogeneity can randomly perturb their optical transition frequencies, which degrades the indistinguishability of photons emitted from separate defects, and hinders their coupling to optical cavities. Here we show that electric fields can be used to tune the optical transition frequencies of single neutral d…
We study single- and multi-quantum transitions of the nuclear spins of ionized arsenic donors in silicon and find quadrupolar effects on the coherence times, which we link to fluctuating electrical field gradients present after the application of light and bias voltage pulses. To determine the coherence times of superpositions of all orders in the 4-dimensional Hilbert space, we use a phase-cycling technique and find that, when electrical effects were allowed to decay, these times scale as expected for a field-like decoherence mechanism such as the interaction with surrounding $^{29}$Si nuclea…
We study temperature evolution of spin accumulation signals obtained by the three-terminal Hanle effect measurements in a nondegenerated silicon channel with a Schottky-tunnel-barrier contact. We find the clear difference in the temperature-dependent spin signals between spin-extraction and spin-injection conditions. In a spin-injection condition with a low bias current, the magnitude of spin signals can be enhanced despite the rise of temperature. For the interpretation of the temperature-dependent spin signals, it is important to consider the sensitivity of the spin detection at the Schottky…
Here we describe a new high frequency/high field continuous wave and pulsed electrically detected magnetic resonance (CW EDMR and pEDMR) setup, operating at 263 GHz and resonance fields between 0 and 12 T. Spin dependent transport in illuminated hydrogenated amorphous silicon p-i-n solar cells at 5 K and 90 K was studied by in operando 263 GHz CW and pEDMR alongside with complementary X-band CW EDMR. Benefiting from the superior resolution at 263 GHz, we were able to better resolve EDMR signals originating from spin dependent hopping and recombination processes. 5 K EDMR spectra were found to …
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…
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…
Electrical switching and rectifying properties of the metal-VO2-Si structures, on both p-type and n-type silicon, with vanadium dioxide films obtained by an acetylacetonate sol-gel method, are studied. The switching effect is shown to be due to the semiconductor-to-metal phase transition (SMPT) in vanadium dioxide. The shift of the switching threshold voltage, accompanied by the memory effect, in forward bias of the p-Si-VO2 anisotype heterojunction is observed. To explain this effect, a model is proposed which suggests the existence of an additional series resistance associated with a channel…
In a recent publication, we demonstrated electrical spin injection and detection in n-type silicon at temperatures up to 500K using ferromagnetic metal / SiO2 tunnel barrier contacts in a three-terminal geometry (Nature Commun. 2:245 doi:10.1038/ncomms125 (2011)). In comparing our measured spin-voltage signal with the value predicted by theory, we followed the analysis of Tran et al, (Phys. Rev. Lett. 102, 036601 (2009)), and inadvertently propagated an error found therein. As they note in a recent erratum (arXiv:0810.4770v2), the correct expression for the spin resistance area product from th…
Improvement in film growth technology requires a knowledge of the correlation between microstructural and deposition parameters with electrical properties in hydrogenated microcrystalline Si films. Our study indicates that fractional compositions of the constituent crystallite grains in fully crystallized undoped microcrystalline Si films is a unique microstructural feature that defines the film microstructure and can be well correlated to the electrical transport properties as well.
A systematic study to investigate the effects of X-ray exposure on electrical properties of silicon dioxide thin films using X-ray photoelectron spectroscopy
We report the synthesis and the electrical properties of fullerene-based molecular junctions on silicon substrate in which the highly π-conjugated molecule C60 (πquantum well) is isolated from the electrodes by alkyl chains (σtunnel barriers). Initially, the Si/SiO2/\sigmaC60 architecture was prepared either by sequential synthesis (3 different routes) or by direct grafting of the presynthesized C60-σ-Si(OEt)3 molecule. We described the chemical synthesis of these routes and the physico-chemical properties of the molecular monolayers. Then, the second σtunnel barrier was added on the Si/SiO2/σ…
Nominally undoped silicon nanowires (NW) were grown by catalytic chemical vapor deposition. The growth process was optimized to control the NWs diameters by using different Au catalyst thicknesses on amorphous SiO2, Si3N4, or crystalline-Si substrates. For SiO2 substrates an Ar plasma treatment was used to homogenize the catalyst coalescence, and thus the NWs diameter. Furthermore, planar field effect transistors (FETs) were fabricated by implementing 10 to 30 nm thin nominally undoped Si-NWs as the active region. Various silicides were investigated as Schottky-barrier source and drain contact…
Space-grade Si and GaAs solar cells were irradiated with 15 & 40 MeV Li ions. Illuminated (AM0 condition) and unilluminated I-V curves reveal that the effect of high-energy Li ion irradiation has produced similar effects to that of proton irradiation. However, an additional, and different, defect mechanism is suggested to dominate in the heavier-ion results. Comparison is made with proton-irradiated solar-cell work and with non-ionizing energy-loss (NIEL) radiation-damage models.
We analyze the effect of low dimensionality on the electrical conductivity (σ) and Seebeck coefficient (S) in ultra-narrow Si nanowires (NWs) by employing atomistic considerations for the electronic structures and linearized Boltzmann transport theory. We show that changes in the geometrical features of the NWs such as diameter and orientation, mostly affect σ and S in two ways: i) the distance of the band edges from the Fermi level (ηF) changes, and ii) quantum confinement in some cases strongly affect the effective mass of the subbands, which influences the conductivity of the NWs and ηF. Ch…
The capabilities of a simulation tool for the in-depth analysis of the thermal impacts on the performances of solar cells are described. TASC-1D (Thermal Analysis of Solar Cells - 1D, version cSi) solves the coupled electrical, radiative and thermal transport problems for a crystalline silicon cell, as a function of irradiation and thermal conditions. In addition to the electrical outputs that are obtained with the existing simulation tools, it provides the cell equilibrium temperature as well as the spatial and spectral distributions of many relevant quantities. The physical modeling and asso…
Porous silicon (PSi) layers has been prepared in this work via photoelectrochemical (PEC) etching process of an n type silicon wafers of two resistivities (3.5 ohm.cm and 0.02 ohm.cm) in hydrofluoric (HF) acid of 24.5 precent concentration at different etching times (5 to 25 min). The irradiation has been achieved using laser beam of 2W power and 810 nm wavelength. We have studied the morphological and structural properties of PSi layers using the techniques of Xray Diffraction (XRD) and Scanning Electron Microscopy (SEM) and Gravimetric method. The Xray Diffraction data shows that the struc…
We have studied the electrical conductivity behavior of highly crystallized undoped hydrogenated microcrystalline silicon films having different microstructures. The dark conductivity is seen to follow Meyer Neldel rule (MNR) in some films and anti MNR in others, which has been explained on the basis of variation in the film microstructure and the corresponding changes in the effective density of states distributions. A band tail transport and statistical shift of Fermi level are used to explain the origin of MNR as well as anti-MNR in our samples. The observation of MNR and anti MNR in electr…
We report on the structure and electrical characteristics of silicon nanowire arrays prepared by metal assisted chemical etching (MACE) method, investigated by cross-sectional scanning electron microscopy (SEM) and high resolution X-ray diffraction (HR-XRD) methods. SEM micrographs show arrays of merged parallel nanowires, with lengths of 700 nm and 1000 nm, resulted after 1.5 min and 5 min etching time, respectively. X-ray reciprocal space maps (RSMs) around Si (004) reciprocal lattice point indicate the presence of 0D structural defects rather than of extended defects. The photoluminescence …
Using silicon MOSFETs with thin (5nm) thermally grown SiO2 gate dielectrics, we characterize the density of electrically active traps at low-temperature after 16keV phosphorus ion-implantation through the oxide. We find that, after rapid thermal annealing at 1000oC for 5 seconds, each implanted P ion contributes an additional 0.08 plus/minus 0.03 electrically active traps, whilst no increase in the number of traps is seen for comparable silicon implants. This result shows that the additional traps are ionized P donors, and not damage due to the implantation process. We also find, using the roo…
Silicon carbide nanoparticles with diameters around 8 nm and with narrow size distribution have been finely mixed with doped silicon nanopowders and sintered into bulk samples to investigate the influence of nanoinclusions on electrical and thermal transport properties. We have compared the thermoelectric properties of samples ranging from 0-5% volume fraction of silicon carbide. The silicon carbide nanoinclusions lead to a significant improvement in the thermoelectric figure of merit, ZT, largely due to an enhancement of the Seebeck coefficient. A semiclassical Boltzmann transport equation is…
NbSe3 exhibits remarkable anisotropy in most of its physical properties and has been a model system for studies of quasi-one-dimensional charge-density-wave (CDW) phenomena. Herein, we report the synthesis, characterization, and electrical transport of single-crystalline NbSe3 nanoribbons by a facile one-step vapour transport process involving the transport of selenium powder onto a niobium foil substrate. Our investigations aid the understanding of the CDW nature of NbSe3 and the growth process of the material. They also indicate that NbSe3 nanoribbons have enhanced CDW properties compared to…
We study the electrical detection of spin accumulation at a ferromagnet-silicon interface, which can be verified by measuring a Hanle effect in three-terminal lateral devices. The device structures used consist of a semiconducting Si channel and a high-quality Schottky tunnel contact. In a low current-bias region, the Hanle-effect curves are observed only under forward bias conditions. This can be considered that the electrical detectability of the forward-biased contact is higher than that of the reverse-biased contact. This is possible evidence for the detection of spin-polarized electrons c…
