Chemical vapor deposition of germanium onto the silicon (001) surface at atmospheric pressure and 600 degrees Celsius has previously been shown to produce distinct families smaller (up 6 nanometers high) larger (all approximately 15 nanocrystals. Under ultrahigh-vacuum conditions, physical same substrate temperature growth rate produced a similar bimodal size distribution. In situ scanning tunneling microscopy revealed that square-based pyramids transform abruptly during significantly...

Highly sensitive and sequence-specific DNA sensors were fabricated based on silicon nanowires (SiNWs) with single stranded (ss) probe molecules covalently immobilized the nanowire surfaces. Label-free complementary (target) ss-DNA in sample solutions recognized when target was hybridized attached SiNW surfaces, producing a change of conductance SiNWs. For 12-mer oligonucletide probe, 25 pM solution detected easily (signal/noise ratio > 6), whereas 12-mers one base mismatch did not produce...

Hall-mobility measurements have been performed on polycrystalline silicon films deposited a oxide surface by the thermal decomposition of silane. Samples with doping impurities added during deposition or diffusion from doped vapor-deposited showed similar behavior. For both n-type and p-type samples approximately 5 μ thick, mobility reached maximum value about 40 cm2/V sec at free carrier concentration 1018 cm−3 decreased for higher lower concentrations. The observed Hall was generally in...

Dopant segregation at grain boundaries in polycrystalline silicon has been investigated. Arsenic, phosphorus, and boron were ion implanted into low-pressure, chemically-vapor-deposited polycrystalline-silicon films. All films then annealed 1000 °C for 1 h, some subsequently further 800, 850, or 900 64, 24, 12 respectively. For phosphorus arsenic the room-temperature resistivity of was found to be higher after annealing lower temperatures. By successively same sample temperatures, would...

We synthesized up to Ge0.914Sn0.086 alloys on (100) GaAs/InyGa1−yAs buffer layers using molecular beam epitaxy. The enable engineered control of strain in the Ge1−xSnx reduce strain-related defects and precipitation. Samples grown under similar conditions show a monotonic increase integrated photoluminescence (PL) intensity as Sn composition is increased, indicating changes bandstructure favorable for optoelectronics. account bandgap from determine direct bowing parameter b = 2.1 ± 0.1....

This report summarizes observations of Ge island formation during growth on Si(001) by chemical vapor deposition from germane in the pressure range 10 Torr to atmospheric a conventional epitaxial reactor. A four-step process is observed: (1) uniform pseudomorphic overlayer (“wetting’’ layer) formation; (2) three-dimensional with constant aspect ratio; (3) continued diameter and increasing height; (4) rapid larger, faceted islands. Ostwald ripening islands heat treatment after terminating...

Si nanowires grow rapidly by chemical vapor deposition on Ti-containing islands surfaces when an abundant supply of Si-containing gaseous precursor is available. The density wires approximately the same as nucleating surface, although at least two different types appear to correlate with very wire growth rates. For conditions used, a minority long, defect-free form, along more numerous containing defects. Energy-dispersive x-ray spectroscopy shows that nanoparticles remain tip growing wires....

Ge islands were deposited on Si(001) partially covered with patterned oxide. Selective Si was some wafers before deposition to form raised plateaus well-defined sidewall facets. On narrow lines, the locate preferentially at edges of regions, and preference is strongest narrowest patterns aligned along a 〈100〉 direction. For 450 nm wide plateau in this direction, all are positioned pattern, 300 space near center pattern free islands. The appear be uniformly spaced edges. wider several rows...

The evolution of the shape and size distributions Ge islands on Si(001) during annealing after deposition has been studied at different temperatures effective coverages. initial square-based pyramids, elongated “hut” structures, faceted “dome-shaped” islands, much larger “superdomes” depends conditions. During deposition, coarsen over a limited range times temperatures. Those pyramidal-shaped that grow transform to faceted, dome-shaped as they become larger. Initially dissolve pyramidal...

We report a model of nanowire (NW) mechanics that describes force vs displacement curves over the entire elastic range for diverse wire systems. Due to clamped-wire measurement configuration, response in linear regime can be or nonlinear, depending on system and displacement. For Au NWs is essentially since yielding occurs prior onset inherent nonlinearity, while Si highly followed by brittle fracture. Since method deformation, it unequivocally identifies yield points both these materials.

We report simultaneous lateral growth of a high density highly oriented, metal-catalyzed silicon nanowires on patterned substrate and bridging between two vertical sidewalls, which can be developed into electrodes an electronic device. After angled deposition catalytic metal nanoparticles one opposing surfaces, we used chemical vapour process to grow eventually form mechanically robust 'nanobridges'. The these nanowire arrays integrated with existing processes. This method connecting...

We demonstrate an electroabsorption modulator on a silicon substrate based the quantum confined Stark effect in strained germanium wells with silicon-germanium barriers. The peak contrast ratio is 7.3 dB at 1457 nm for 10 V swing, and exceeds 3 from 1441 to 1461 nm. novel side-entry structure employs asymmetric Fabry-Perot resonator oblique incidence. Unlike waveguide modulators, design insensitive positional misalignment, maintaining > while translating incident beam 87 mum 460 orthogonal...

The structure of silicon films deposited by low pressure, chemical vapor deposition in the 600°C temperature range has been investigated x‐ray diffraction and transmission electron microscopy. There is a critical near 600°C, above which are polycrystalline below amorphous obtained. This close to that used deposit for integrated circuit applications. When polycrystalline, <110> texture dominates. reasonably stable upon annealing temperatures up approximately 1100°C. initially films, however,...

Chemical vapor deposition by Au-catalyzed decomposition of GeH4 has been used to grow Ge nanowires on single-crystal silicon. The over the temperature range ∼320−380 °C under conditions used, probably vapor−liquid−solid (VLS) process. low-temperature growth aids integration with conventional electronic devices. At optimum near 320 °C, many are epitaxially oriented substrate crystal structure, growing in 〈111〉 directionsat an oblique angle (001)-oriented Si substrates and nearly vertically...

Transistors have been fabricated with their active channels in thin films of polycrystalline silicon. A subsequent hydrogen plasma treatment has used to improve the transistor properties significantly by reducing number electrically grain-boundary defects. Plasma conditions maximize hydrogenation effect briefly investigated.

A new phenomenological model for the electrical conduction in polycrystalline silicon is developed. The combined mechanisms of dopant segregation, carrier trapping, and reflection at grain boundaries are proposed to explain silicon. assumed behave as an intrinsic wide-band-gap semiconductor forming a heterojunction with grains. Thermionic emission over potential barriers created within grains due trapping then tunneling through transport mechanism. generalized current-voltage relationship...

We present observations of quantum confinement and quantum-confined Stark effect (QCSE) electroabsorption in Ge wells with SiGe barriers grown on Si substrates, good agreement theoretical calculations. Though is an indirect gap semiconductor, the resulting effects are at least as clear strong seen typical III-V well structures similar wavelengths. also demonstrate that can be over C-band around 1.55-mum wavelength heated to 90degC, operating temperature silicon electronic chips. The physics...

Silicon films deposited by low pressure chemical‐vapor deposition over the temperature range from 525° to 725°C were investigated. It was found that polycrystalline are formed above 600°C and more stable than amorphous at lower temperatures. Their crystal structure is a strong function of weaker rate. Either {110} or {100} texture may dominate structure, depending primarily on temperature. The electrical resistance obtained doping LPCVD as maximum for temperatures (near 600°C), although this...