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Extending the resolution and spatial proximity of lithographic patterning below critical dimensions of 20 nm remains a key challenge with very-large-scale integration, especially if the persistent scaling of silicon electronic devices is sustained. One approach, which relies upon the directed self-assembly of block copolymers by chemical-epitaxy, is capable of achieving high density 1 : 1 patterning with critical dimensions approaching 5 nm. Herein, we outline an integration-favourable strategy for fabricating high areal density arrays of aligned silicon nanowires by directed self-assembly of a PS-b-PMMA block copolymer nanopatterns with a L(0) (pitch) of 42 nm, on chemically pre-patterned surfaces. Parallel arrays (5 × 10(6) wires per cm) of uni-directional and isolated silicon nanowires on insulator substrates with critical dimension ranging from 15 to 19 nm were fabricated by using precision plasma etch processes; with each stage monitored by electron microscopy. This step-by-step approach provides detailed information on interfacial oxide formation at the device silicon layer, the polystyrene profile during plasma etching, final critical dimension uniformity and line edge roughness variation nanowire during processing. The resulting silicon-nanowire array devices exhibit Schottky-type behaviour and a clear field-effect. The measured values for resistivity and specific contact resistance were ((2.6 ± 1.2) × 10(5)Ωcm) and ((240 ± 80) Ωcm(2)) respectively. These values are typical for intrinsic (un-doped) silicon when contacted by high work function metal albeit counterintuitive as the resistivity of the starting wafer (∼10 Ωcm) is 4 orders of magnitude lower. In essence, the nanowires are so small and consist of so few atoms, that statistically, at the original doping level each nanowire contains less than a single dopant atom and consequently exhibits the electrical behaviour of the un-doped host material. Moreover this indicates that the processing successfully avoided unintentional doping. Therefore our approach permits tuning of the device steps to contact the nanowires functionality through careful selection of the initial bulk starting material and/or by means of post processing steps e.g. thermal annealing of metal contacts to produce high performance devices. We envision that such a controllable process, combined with the precision patterning of the aligned block copolymer nanopatterns, could prolong the scaling of nanoelectronics and potentially enable the fabrication of dense, parallel arrays of multi-gate field effect transistors.

Access to the full text of the published version may require a subscription. Differences in the ligand conformations on the surface of the Au nanoparticles and phase separation of the fluorocarbon/CO2 and hydrocarbon/toluene systems, gave rise to greater steric stabilisation of 2 the fluorous-capped Au nanoparticles in CO2, resulting in small diameter nanowires with a relatively narrow size distribution. Electrical analysis of the nanowires showed them to be p-type (hole) Rightssemiconductors.

Composites of zinc hydroxide with graphite-oxide and graphite derived material are prepared using in situ precipitation of Zn(OH) 2 in the presence of the dispersed graphite-based phases. The new materials are characterized by a range of methods, including SEM, infrared and Raman spectroscopy, thermal analysis, potentiometric titration, nitrogen adsorption, XPS, and electrical measurements. The results indicate that the final properties of the composites are determined by a complex interplay between the two components. When graphite-oxide is used, its oxygen containing functional groups are involved during synthesis with a zinc hydroxide precursor, leading to the formation of interface bonds between the inorganic and carbon-based phase. This new interface not only affects the chemistry of the materials but also determines texture and porosity. Another conversion of the inorganic phase to zinc oxide via thermal treatment further affects the properties of the composite, leading to the formation of additional chemical bonds between the zinc oxide and graphite-oxide phases. Even though the addition of graphite-oxide results in a highly porous material of heterogeneous nature, the thermally treated composite has a comparable electrical conductivity to the zinc hydroxide-graphite derived material composite, although having a lower density. This is attributed to the increased abundance of sp 2 hybridization, the presence of Zn 0 , and improved local electrical connectivity between the two phases of the composite through the new interface bonds.

Resistance contributions in a nanowire device are determined accurately. Resistance in silver nanowires, such as conduction‐channel and contact resistance, including current‐crowding effects, reveal both the true nanowire resistivity and the overall device performance, including dissipation and scaling potential. A comprehensive study on the device layout, the contact geometry and, most importantly, the transfer length over which charge injection between contact electrode and nanowire occurs, is performed.