Search results

Direct measurements are presented of the Schottky barrier (SB) heights of carbon nanotube devices contacted with Pd electrodes. The SB barrier heights were determined from the activation energy of the temperature-dependent thermionic emission current in the off-state of the devices. The barrier heights generally decrease with increasing diameter of the nanotubes and they are in agreement with the

Semiconducting carbon nanotubes (CNTs) are attractive as channel material for field-effect transistors due to their high carrier mobility. In this paper we show that a local CNT gate can provide a significant improvement in the subthreshold slope of a CNT transistor compared to back gate switching and provide gate delays as low as 5 ps. The CNT gated CNT transistor devices are fabricated using a t

A cryogenic bolometer has been fabricated using a bundle of single-walled carbon nanotubes as absorber. A bolometric response was observed when the device was exposed to radiation at 110 GHz. The temperature response was 0.4 mV/K, with an intrinsic electrical responsivity at low frequency up to 109 V/W and noise equivalent power of 3 × 10-16 W/Hz1/2 at 4.2 K. The response is largest at input power

Cross junctions of carbon nanotubes (CNTs) separated by thin oxide layers have been fabricated, in which the top CNT is used as a local gate to control the electron transport through the lower CNT. Coulomb oscillation was observed in the lower CNTs at low temperatures. The gating field from the upper CNTs is seen to modulate the band structure in the lower CNTs, producing double quantum dot system

The application of an electric field while growing carbon nanotubes with CVD can induce deformations in the SiO2 substrate. The effect is attributed to field emission from the tubes and Marangoni convection in a small molten SiO2 region underneath the tubes. Postgrowth deformation has been performed as well as large scale deformations using the collective effect of many field emitters. The porosit

The contacts of single carbon nanotubes and bundles of carbon nanotubes with superconducting and metallic electrodes are investigated in order to create bolometers and electron coolers. Tunneling contacts of the carbon nanotubes with aluminum electrodes are obtained. The current-voltage characteristics of junctions are analyzed for temperatures from room temperature to 300 mK. The resistance of in

We consider the role of electric fields during metal-catalysed thermal chemical vapour deposition growth of carbon nanotubes and show that enhanced growth occurs from a negatively biased electrode. An electric field, applied externally to the growing tubes and/or generated as a result of electron emission or self-biasing, may strongly affect the carbon supply through the catalyst nanoparticle, enh

We have developed a method to fabricate crossed junctions between semiconducting (s) and metallic (m) carbon nanotubes (CNTs) combining electric field directed chemical vapor deposition growth and dielectrophoretic alignment. By separating the s- and m-CNTs with a thin dielectric an ultrasmall field effect transistor (FET) was fabricated. By using the m-CNT as a gate it was possible to modulate th

Intense local heating of Si O2 is shown to occur during chemical vapor deposition growth of single-walled carbon nanotubes in the presence of an electric field. This gives rise to the Marangoni effect where strong convection currents are induced in the molten Si O2 layer. Nanoscale trenches and bumps are formed in the insulating layer directly below the growing nanotube.

Chemical transformation of single-wall carbon nanotubes (SWNT), edge-terminated with carboxylic groups, to SWNT species with amino groups directly attached to the tube open ends has been performed. Different synthetic approaches have been investigated. The reaction products were characterised by FTIR, Raman spectroscopy, XPS and SEM.

Electric field aligned, single-walled carbon nanotubes are grown between electrodes using thermal chemical vapour deposition (CVD) of methane. The growth occurs on a thin film layered catalyst of aluminium, iron and molybdenum patterned on top of electrodes. The nanotubes bridge 10 μm sized electrode gaps and have a typical diameter of less than 2 nm as measured by Raman spectroscopy and atomic fo

This paper presents new estimates of the living standards among the rural labouring classes in Sweden from 1750 to 1900. Starting with a database of more than 1,000 probate inventories of rural landless and semi-landless people from the benchmark years 1750, 1800, 1850 and 1900, we study the development for crofters in particular. We measure their assets and debts in great detail, mapping the deve

The Swedish book business began as a poorly developed market with serious economic, social, and infrastructural issues, but transformed over the course of two centuries into a well-functioning, albeit small, market with strong international ties. The 19th-century book market was hampered by poor infrastructure and underdeveloped publishing and book sales. Technological innovations in printing tech

The brain operates at a critical point that is balanced between order and disorder. Even during rest, unstable periods of random behavior are interspersed with stable periods of balanced activity patterns that support optimal information processing. Being born preterm may cause deviations from this normal pattern of development. We compared 33 extremely preterm (EPT) children born at < 27 weeks of

The streaming instability is a leading candidate mechanism to explain the formation of planetesimals. However, the role of this instability in the driving of turbulence in protoplanetary disks, given its fundamental nature as a linear hydrodynamical instability, has so far not been investigated in detail. We study the turbulence that is induced by the streaming instability as well as its interacti

It is clearly evident from recent developments that government authorities in many respects have failed to gain full control over the citizens of our country. This is especially notable in relation to the problems that have arisen from the spread of so-called grey and black markets and the associated increase in the number of transactions that have evaded taxation. This is not just an efficiency p