Droplet dynamics in controlled InAs nanowire interconnections.

Semiconductor nanowires offer a versatile platform for the fabrication of new nanoelectronic and nanophotonic devices. These devices will require a high level of control of the nanowire position in relation to both other components of the device and to other nanowires. We demonstrate unprecedented control of the position of InAs nanowires using selective-area vapor-liquid-solid epitaxy (VLS) on an InP ridge template.

Two- and three-electron Pauli spin blockade in series-coupled triple quantum dots.

We investigate two- and three-electron spin blockade in three vertical quantum dots (QDs) coupled in series. Two-electron spin blockade is found in a region where sequential tunneling through all QDs is forbidden but tunneling involving virtual hopping through an empty QD is allowed. It is observed only for the hole cycle with a distinct bias threshold for access to the triplet state.

Coherent three-level mixing in an electronic quantum dot.

We observe magnetic-field-induced level mixing and quantum superposition phenomena between three approaching single-particle states in a quantum dot probed via the ground state of an adjacent quantum dot by single-electron resonant tunneling. The mixing is attributed to anisotropy and anharmonicity in realistic dot confining potentials. The pronounced anticrossing and transfer of strengths (both enhancement and suppression) between resonances can be understood with a simple coherent level mixing model.

Chemical vapour deposition of single walled carbon nanotubes freely suspended over nanotube supports.

Single walled carbon nanotubes (SWNTs) suspended above the substrate can be fabricated simply and rapidly by chemical vapour deposition growth over pre-grown multi-walled carbon nanotubes (MWNTs). SWNTs are suspended either on a randomly organized carbon nanotube network on an unpatterned substrate, or between organized pillars made from vertically aligned nanotube forests on a patterned substrate. All nanotubes are produced during a single growth run using a two step growth technique.

Photoluminescence imaging of suspended single-walled carbon nanotubes.

Single-walled carbon nanotubes (SWNTs) suspended in air over trenches are imaged using their intrinsic near-infrared (NIR) photoluminescence (1.0-1.6 microm).