The growth of III-V semiconductors on silicon would allow the integration of their superior (opto-)electronic properties with silicon technology. But fundamental issues such as lattice and thermal expansion mismatch and the formation of antiphase domains have prevented the epitaxial integration of III-V with group IV semiconductors. Here we demonstrate the principle of epitaxial growth of III-V nanowires on a group IV substrate. We have grown InP nanowires on germanium substrates by a vapour-liquid-solid method. Although the crystal lattice mismatch is large (3.7%), the as-grown wires are monocrystalline and virtually free of dislocations. X-ray diffraction unambiguously demonstrates the heteroepitaxial growth of the nanowires. In addition, we show that a low-resistance electrical contact can be obtained between the wires and the substrate.

Atomic layer deposition (ALD) is used in applications where inorganic material layers with uniform thickness down to the nanometer range are required. For such thicknesses, the growth mode, defining how the material is arranged on the surface during the growth, is of critical importance. In this work, the growth mode of the zirconium tetrachloride∕water and the trimethyl aluminum∕water ALD process on hydrogen-terminated silicon was investigated by combining information on the total amount of material deposited with information on the surface fraction of the material. The total amount of material deposited was measured by Rutherford backscattering, x-ray fluorescence, and inductively coupled plasma–optical emission spectroscopy, and the surface fractions by low-energy ion scattering. Growth mode modeling was made assuming two-dimensional growth or random deposition (RD), with a “shower model” of RD recently developed for ALD. Experimental surface fractions of the ALD-grown zirconium oxide and aluminum oxide films were lower than the surface fractions calculated assuming RD, suggesting the occurrence of island growth. Island growth was confirmed with transmission electron microscopy (TEM) measurements, from which the island size and number of islands per unit surface area could also be estimated. The conclusion of island growth for the aluminum oxide deposition on hydrogen-terminated silicon contradicts earlier observations. In this work, physical aluminum oxide islands were observed in TEM after 15 ALD reaction cycles. Earlier, thicker aluminum oxide layers have been analyzed, where islands have not been observed because they have already coalesced to form a continuous film. The unreactivity of hydrogen-terminated silicon surface towards the ALD reactants, except for reactive defect areas, is proposed as the origin of island growth. Consequently, island growth can be regarded as “undesired surface-selective ALD.”

Electron emission measurements were conducted on individual carbon nanotubes. The nanotubes had a closed end and their surfaces were thoroughly cleaned. It is shown conclusively that individual carbon nanotube electron emitters indeed exhibit Fowler–Nordheim behavior and have a work function of 5.1±0.1eV for the nanotubes under investigation, which had diameters of 1.4 and 4.9nm.

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The authors investigate the implications of amorphizing ion implants on the crystalline integrity of sub-20nm wide fin field-effect transistors (FinFETs). Recrystallization of thin body silicon is not as straightforward as that of bulk silicon because the regrowth direction may be parallel to the silicon surface rather than terminating at it. In sub-20nm wide FinFETs surface proximity suppresses crystal regrowth and promotes the formation of twin boundary defects in the implanted regions. In the case of a 50nm amorphization depth, random nucleation and growth leads to polycrystalline silicon formation in the top ∼25nm of the fin, despite being only ∼25nm from the crystalline silicon seed.

High-speed rewritable optical disks based on conventional (eutectic) Sb–Te phase-change materials have low archival life stability and high media noise. We propose Te-free, Sb-based phase-change materials for recording at linear velocities over 28 m/s. These materials combine good optical contrast, rapid crystallization, and high amorphous phase stability.

The structural changes in carbon nanotubes under electron emission conditions were investigated in situ in a transmission electron microscope (TEM). The measurements were performed on individually mounted free-standing multi-walled carbon nanotubes (CNTs). It was found that the structure of the carbon nanotubes did not change gradually, as is the case with field emission electron sources made of sharp metal tips. Instead, changes occurred only above a current level of a few microamperes, which was different for each nanotube. Above the threshold current, carbon nanotubes underwent either structural damage, such as shortening and splitting of the apex of the nanotube, or closing of their open cap. The results are discussed on the basis of several models for degradation mechanisms.

Individual multiwalled carbon nanotubes were mounted on tungsten support tips in a scanning electron microscope equipped with a nanomanipulator. It was possible to select the diameter of the nanotube to align the nanotube with respect to the tip axis and to tune the contact length of the nanotube and the support tip. We have also developed a way to control the length of the nanotube protruding from the support tip. Control over the nature of the nanotube cap was not obtained.