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Search for "contacts" in Full Text gives 331 result(s) in Beilstein Journal of Nanotechnology. Showing first 200.
Process-specific mechanisms of vertically oriented graphene growth in plasmas
Beilstein J. Nanotechnol. 2017, 8, 1658–1670, doi:10.3762/bjnano.8.166
- -probe contacts and an Agilent B2902A precision source/measure unit was used to estimate sheet resistance in van der Pauw geometry. Author contributions S. G. planned, performed the experiments, analyzed the data and wrote the manuscript. S. R. P. carried out scanning electron microscopy. S. R. P., N. K
Group-13 and group-15 doping of germanane
Beilstein J. Nanotechnol. 2017, 8, 1642–1648, doi:10.3762/bjnano.8.164
- oxidation of As occurs. The As 2p3/2 peak centered at 1323 eV in as-grown As:GeH starts disappearing in favor of a 1326.1 eV [35] oxidized state. The effect of dopants on the electronic transport of single-crystal flakes of Ga:GeH and As:GeH were measured with contacts fabricated by using a shadow mask
- technique (Figure 5b). Two-probe I–V measurements were carried out on single crystals with device geometries that typically featured a channel length of 25 µm, a width of 2–4 mm and a thickness of 5–20 µm (Figure 5b). After exploring numerous metals, nearly ohmic contacts (under vacuum) to Ga:GeH were
- observed using 100 nm Au as a contact metal. Furthermore, the highest ambient and vacuum conductivities in As:GeH were achieved when contacting with Ag (80 nm)/Au (20 nm). The fact that Au with its higher work function is needed to make ohmic contacts for Ga:GeH, compared to Ag for As:GeH, suggests that Ga
Parylene C as a versatile dielectric material for organic field-effect transistors
Beilstein J. Nanotechnol. 2017, 8, 1532–1545, doi:10.3762/bjnano.8.155
- . Parylene C forms transparent, pinhole-free conformal coatings of thicknesses as low as 0.1 μm with excellent dielectric and mechanical properties. Increasing thickness to 0.2 mm suffices to uniformly cover rough colloidal-graphite contacts. Transistors with rubrene as semiconductor and parylene as
- configuration (0.02 cm2/Vs) [58]. Changes in the surface energy between Parylene C (bottom gate, top contacts) and glass with gold electrodes (top gate, bottom contacts) are the main factor responsible for variations in the organization of semiconductor molecules. Additionally, parameters such as wettability
- characteristics measured during the continuous bias stress of 125 h. (a) Bottom-gate, top-contacts, (b) top-gate, bottom-contacts, and (c) dual-gate OFETs. Reprinted from [54], copyright 2014 American Chemical Society. Volumetric reconstruction of the Parylene C-coated microscopy glass (left, atop) and calculated
Charge transport in organic nanocrystal diodes based on rolled-up robust nanomembrane contacts
Beilstein J. Nanotechnol. 2017, 8, 1277–1282, doi:10.3762/bjnano.8.129
- challenge due to difficulties in creating non-destructive contacts [14][15][16]. Although there have been remarkable advances in the methods for vertically contacting a variety of organic thin films, one of the main challenges to perform such fabrication still lies in the preparation of reliable vertical
- ], indirect evaporation [22][23], ‘ready-made’ approaches [24][25], and robust mechanical contacts [26][27][28][29], the rolled-up nanotechnology provides the precise positioned electrodes and high fabrication yield of array devices, and does not require the chemical modification of functional organic layers
- previous report, organic nanocrystal diodes have been successfully developed, in which rolled-up nanomembranes provide robust contacts to fully unleash the advantages of organic nanocrystals for sensing gas molecules [19]. Apart from the demonstration of functional nanodevices, the investigation and
Metal oxide nanostructures: preparation, characterization and functional applications as chemical sensors
Beilstein J. Nanotechnol. 2017, 8, 1205–1217, doi:10.3762/bjnano.8.122
- transducer. In order to have a stable chemical sensor, not only the active material, but all the components of the device, such as electrical contacts and heating system, must be stable and reliable. The scope of this manuscript is to present different techniques for the preparation of nanostructures, and to
Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins
Beilstein J. Nanotechnol. 2017, 8, 1191–1204, doi:10.3762/bjnano.8.121
- which symmetry-related molecules with planar porphyrin cores interact with each other by, for example, formation of intermolecular ZnII…O contacts. Further intermolecular interactions refer to those that were described in detail by, for example, Goldberg et al. [14] or by us [15]. In contrast, saddle
Growth, structure and stability of sputter-deposited MoS2 thin films
Beilstein J. Nanotechnol. 2017, 8, 1115–1126, doi:10.3762/bjnano.8.113
- exposed to visible light radiation and local temperature increase. Electrical properties of MoS2 thin films In order to investigate the electrical properties of our PVD MoS2 films on the SiO2-covered Si substrates two types of FET devices with rectangular and circular source and drain contacts were
- (with some devices showing higher resistances, which might however be related to non-continuous film regions under the contacts), in all our measurements we find no response to the applied gate bias. Since bulk MoS2 in its most stable 2H form is a semiconductor [8] the observation of such metallic-like
- (FET) devices with rectangular and circular contacts have been made. The drain/source contacts were defined by means of optical lithography. The Ti/Au (5/50 nm) contact pads have been fabricated by means of thermal evaporation. As the global back gate to the FET devices the highly doped Si wafer under
Stable Au–C bonds to the substrate for fullerene-based nanostructures
Beilstein J. Nanotechnol. 2017, 8, 1073–1079, doi:10.3762/bjnano.8.109
- Au is very fast at room temperature, individual molecules cannot be stabilized and contacted outside islands. This has important consequences for single-molecule transport, where it would be desirable to have reliable and stable metal–molecule contacts. In the case of molecular spintronics, the
The integration of graphene into microelectronic devices
Beilstein J. Nanotechnol. 2017, 8, 1056–1064, doi:10.3762/bjnano.8.107
- devices. Generally speaking the crucial issues for graphene integration are identified today and the corresponding research tasks can be clearly defined. Keywords: contacts; deposition; encapsulation; graphene; process integration; Introduction Since the discovery of the electronic properties of
- should be manageable with respect to device manufacturing. 5 Contacts Because the performance of an electronic device, e.g., a transistor, is strongly affected by parasitic effects such as contact resistances (the contact resistance should not exceed 10% of the channel resistance), this issue is of
- enormous importance, especially for short-channel devices. Numerous studies have been published during the last few years on the understanding and improvement of graphene–metal contacts, reporting contact resistivity values in a wide range from several ohm-micrometers to several hundred thousand ohm
CVD transfer-free graphene for sensing applications
Beilstein J. Nanotechnol. 2017, 8, 1015–1022, doi:10.3762/bjnano.8.102
- gold contacts with wire-bonds are clearly visible. As can be seen, accurately defined multilayer graphene patterns down to micrometre-size can be obtained using this method. From an electrical point of view, the fabrication technique has proven to be quite repeatable and uniform, since devices with the
- SiO2. Cr/Au metal contacts have finally been patterned by a lift-off process to design a four-point probe structure. The final chemiresistive devices consist of a material strip 206 µm long and 5 µm wide, placed between two couples of metal electrodes (Figure 1). Raman analyses have been performed at
Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins
Beilstein J. Nanotechnol. 2017, 8, 863–871, doi:10.3762/bjnano.8.88
- measurements, the tip–sample contact is mechanically vibrated at various frequencies to detect the so called “contact resonance frequencies”. These CR-frequencies are characteristic of the tip–sample contact stiffness (higher frequencies for stiffer contacts) and depend on the mechanical properties of the tip
- considering the blanket film as a reference with a modulus of 3.5 GPa and reporting all the measured values of contact stiffness to the contact stiffness measured on the blanket film. The tip–sample contacts were treated as Hertz contacts [33]. Results and Discussion To monitor changes in the chemical
Measuring adhesion on rough surfaces using atomic force microscopy with a liquid probe
Beilstein J. Nanotechnol. 2017, 8, 813–825, doi:10.3762/bjnano.8.84
- widely varying heights, shapes and relative distances (Figure 2). In summary, larger contact lengths lead to larger deformations of the solid or liquid probe, and possibly of the substrate, which results in a larger pull-off force due to the increase of contacts. We point out that the pull-off forces for
- number of contacts between the glass sphere and the peaks for each run. The number of contacts we find in this system ranges between 1 and 5 as shown in Figure 10a. The low number of contacts in this case, the relative insensibility of the pull-off force to the contact length, and the high stiffness of
- measured for a contact line pinned on a strong defect on a carbon nanotube dipped in a liquid, also measured by AFM [35]. Just as before, dividing each measured pull-off force by 14.9 pN, we obtain numbers that are statistically close to integers. In this way, we get the approximate number of contacts
3D Nanoprinting via laser-assisted electron beam induced deposition: growth kinetics, enhanced purity, and electrical resistivity
Beilstein J. Nanotechnol. 2017, 8, 801–812, doi:10.3762/bjnano.8.83
- combination of photolithography and electron beam lithography (EBL) were used to produce the two-contact pads with a spacing of 500 nm. An initial set of gold electrical contacts were patterned using photolithography and deposited with a thickness of 100 nm. A 3 nm titanium adhesion layer was deposited, prior
- to gold sputtering, to promote adhesion between the gold contacts and the underlying, insulating SiO2 film (290 nm). The original photolithographically defined spacing between electrical contacts was 20 µm. EBL was performed using a Raith ELPHY Quantum patterning engine equipped on the FEI NovaLab
Copper atomic-scale transistors
Beilstein J. Nanotechnol. 2017, 8, 530–538, doi:10.3762/bjnano.8.57
- atomic-scale transistor with a copper quantum point contact as switching block. The fabrication and electron-transport properties of metallic point contacts have been investigated both experimentally and theoretically [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. The
- copper atomic-scale point contacts have been fabricated as mechanically controllable break junctions (MCBJ) [42][43][44][45], by using scanning probe microscopy (SPM) with a conductive tip [46][47], or electrochemical techniques [24][25][26][48][49]. Copper is an interconnection material in ultra-large
- for copper deposition on the three microelectrodes source, drain and gate. After the gap between the source and drain electrodes was closed with the deposited copper the deposition process continued for about 20 min to stabilize the contact. The copper point contacts were trained as atomic-scale
Advances in the fabrication of graphene transistors on flexible substrates
Beilstein J. Nanotechnol. 2017, 8, 467–474, doi:10.3762/bjnano.8.50
- smoother substrates. However, it is still possible to identify wrinkles, as indicated by the dashed green circle in Figure 4a. A schematic illustration of the graphene channel fabricated over the FET gate contact is reported in Figure 4b. After patterning the graphene channel, the source and drain contacts
- determine the total electrical resistance, RTOT, between source and drain contacts are also illustrated in Figure 4d. Here, the gate-bias-dependent graphene channel resistance, Rch(Vg), the source and drain contact resistance, Rc, and the access resistance, Racc, associated with the ungated graphene access
- regions between the channel and the source and drain contacts (Lacc = 20 µm length per access region) are shown. The total resistance resulting from the series combination of these contributions can be expressed as: The capacitance of the Al2O3 dielectric deposited by ALD on the flexible substrate was
Study of the surface properties of ZnO nanocolumns used for thin-film solar cells
Beilstein J. Nanotechnol. 2017, 8, 446–451, doi:10.3762/bjnano.8.48
- vertical geometry of these textures, the optical thickness is dictated by the height of the NCs, such that most of the light traversing the cell sees an absorber-layer thickness approximately equal to the NC height. In contrast, as the front and back TCO contacts are interpenetrating, the inter-electrode
Impact of contact resistance on the electrical properties of MoS2 transistors at practical operating temperatures
Beilstein J. Nanotechnol. 2017, 8, 254–263, doi:10.3762/bjnano.8.28
- voltage (Vth). This paper reports a detailed electrical characterization of back-gated multilayer MoS2 transistors with Ni source/drain contacts at temperatures from T = 298 to 373 K, i.e., the expected range for transistor operation in circuits/systems, considering heating effects due to inefficient
- demonstrated using single [3] and multilayers of MoS2 [4]. MoS2 thin films, obtained either by cleavage from the bulk material or by chemical vapor deposition, are typically unintentionally n-type doped. Since well-assessed methods for doping enrichment of MoS2 under source/drain contacts are still lacking
- , MoS2 transistors are mostly fabricated by deposition of metals directly on the unintentionally doped material, resulting in the formation of Schottky contacts. Experimental investigations showed that both low work function (e.g., Sc, Ti) and high work function (e.g., Ni, Pt) metals mostly exhibit a
Influence of hydrofluoric acid treatment on electroless deposition of Au clusters
Beilstein J. Nanotechnol. 2017, 8, 183–189, doi:10.3762/bjnano.8.19
- shown quite interesting applications in the fields of Si nanowire (SiNW) catalysis [1][2][3], metal-assisted etching (MAE) [4] or even as electrical contacts in standard miniaturized devices [5]. Their ability to display enhanced surface plasmon resonance (SPR) at optical frequencies makes them
Studying friction while playing the violin: exploring the stick–slip phenomenon
Beilstein J. Nanotechnol. 2017, 8, 159–166, doi:10.3762/bjnano.8.16
- generally understood to be the resistance to the sliding motion of objects. It is an everyday life phenomenon that originates from the atomic-scale asperities found at the interfacial contacts [1]. However, substantially different physical descriptions apply when friction is studied at the nanoscale
Sensitive detection of hydrocarbon gases using electrochemically Pd-modified ZnO chemiresistors
Beilstein J. Nanotechnol. 2017, 8, 82–90, doi:10.3762/bjnano.8.9
- -like ZnO-based chemiresistive gas sensor. After the annealing at 550 °C, pristine and Pd-modified ZnO were redispersed in ACN and drop-cast on alumina substrates to obtain sensing layers between gold contacts. These assemblies were subsequently thermally stabilized at 300 °C for 2 h. The description of
Structural and tribometric characterization of biomimetically inspired synthetic "insect adhesives"
Beilstein J. Nanotechnol. 2017, 8, 45–63, doi:10.3762/bjnano.8.6
- viscosity of the liquid, in thin films, friction can be enhanced by processes such as (1) the formation of dry contacts by dewetting, (2) the solid-like behaviour of the liquid attributable to non-Newtonian properties, (3) the molecular ordering of the liquid at zones at which the film becomes thinner than
- a few monolayers and (4) the penetration of surface irregularities through the liquid film resulting in solid–solid contacts (cf. discussion in [55]). The influence of film thickness can also be seen in our experiments. Although we assume that in all of our experiments, we measured in the regimes of
Sub-nanosecond light-pulse generation with waveguide-coupled carbon nanotube transducers
Beilstein J. Nanotechnol. 2017, 8, 38–44, doi:10.3762/bjnano.8.5
- -coupled CNT transducers to electrical signals and analyze the optical pulses propagating in the waveguide. Results and Discussion Fabrication of waveguide-integrated CNT emitters Our waveguide-coupled CNT (WG-CNT) transducers consist of three components: a rib waveguide, metallic contacts next to the
- waveguide, and metallic single-walled carbon nanotubes (SWCNTs) placed on top of the waveguide, bridging the contacts (Figure 1a). We use the design and fabrication approach for our samples that has been described in detail elsewhere [4]. Both electrodes and waveguides were defined using several steps of
- electron beam lithography on top of Si3N4/SiO2/Si substrate. Au/Cr contacts were produced by physical vapor deposition, and 600 nm wide, half-etched Si3N4-waveguides were formed with reactive ion etching. A typical sample contains tens of contact pairs and CNTs that were placed in between using
Solvent-mediated conductance increase of dodecanethiol-stabilized gold nanoparticle monolayers
Beilstein J. Nanotechnol. 2016, 7, 2057–2064, doi:10.3762/bjnano.7.196
- 0.76 Å−1 for alkane chains with one and two chemisorbed contacts [30]. Since Δa = 0.5 nm for immersion in EtOH, the conductance would increase by a factor between 190 and 45. On average, the conductance of our monolayers increased by 36 during EtOH immersion, which is slightly lower than the calculated
- samples were rinsed with THF or EtOH and dried under nitrogen flow [3]. Contact deposition Electric contacts were applied by shadow mask evaporation. We aligned a 400 mesh TEM grid with the printed lines on the substrate and deposited 3 nm titanium and 65 nm gold by electron-beam evaporation at a pressure
Zigzag phosphorene nanoribbons: one-dimensional resonant channels in two-dimensional atomic crystals
Beilstein J. Nanotechnol. 2016, 7, 1983–1990, doi:10.3762/bjnano.7.189
- = 57 nanoribbon, as a function of the energy. In order to avoid any coupling between the edge states the width of the nanoribbon in the contacts is also NZ = 60. Transmission plateaus above and below the edge states band are shown, for the sake of completeness, since these structures are of entirely
- ). When mZ is further diminished, the barriers to the upper-edge contacts become too large, but now the coupling to the lower edge becomes relevant. For mZ ≤ 15 transmission shows asymmetric Fano-like resonances at the low-energy side and sharp anti-resonances at higher energies within the central band
- (keeping the central band of the contacts unaltered). In our constriction the role of both channels (discrete states and continuum at the upper and lower edges) can be made explicit by picturing the local density of states (LDOS) in Figure 4, at the energy values indicated by arrows 1, 2, 3 and 4 in Figure
Monolayer graphene/SiC Schottky barrier diodes with improved barrier height uniformity as a sensing platform for the detection of heavy metals
Beilstein J. Nanotechnol. 2016, 7, 1800–1814, doi:10.3762/bjnano.7.173
- behaviour and a good quality of ohmic palladium–graphene contacts. Keeping in mind the strong sensitivity of graphene to analytes we propose the possibility to use the graphene/SiC Schottky diode as a sensing platform for the recognition of toxic heavy metals. Using density functional theory (DFT
- characterization provides evidence for the formation of monolayered graphene [51]. The 1 ML coverage is found to be about 99%, thereby implying the high uniformity of the graphene thickness. To avoid the necessity to etch parts of the graphene coverage in order to form the ohmic contacts to SiC, we did not utilize
- the lateral Schottky diode structure and mainly focused on designing vertical devices. It might be expected that the vertical structure has some advantages over the lateral device, since it offers a simpler design and a higher breakdown voltage (because of larger area efficiency). Palladium contacts
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