The Nanowire is a solid, cylindrical wire with a diameter usually less than 100 nm.Fabrication of Nanowires at surfaces.Nanowires are just like normal electrical wires other than the fact that they are extremely small. Like conventional wires, nanowires can be made from a variety of conducting and semiconducting materials like copper, silver, gold, iron, silicon, zinc oxide and germanium. Nanowires can also be made from carbon nanotubes.
The goal of this project is the design of artificial materials that consist of ultrafine wires or linear arrays of dots, ten to hundred times finer than those produced with commercial micro-structure fabrication techniques. In fact, we have gone all the way down to atom chains which may be viewed as the ultimate nanowires (scroll to the bottom for those). These patterns are formed by self-assembly, where atoms arrange themselves naturally at stepped silicon surfaces.
An important aspect in fabricating nanowires is the ability to prepare wires of an any material on any substrate with any thickness. In particular, using silicon wafers as substrate is highly-desirable. To achieve this goal we suggest the following "universal" process. First, a silicon substrate with a regular array of steps is prepared (A). Then, stripes (B) or dots (C) of a passivating material are attached to the step edges. This part is analogous to creating a photoresist mask in traditional lithography. As mask material we use calcium fluoride, which is lattice-matched to silicon and chemically inert. Eventually, the desired material is deposited on the remaining silicon, for example by substrate-selective chemical vapor deposition (CVD) or electroplating. Alternatively, calcium fluoride could become useful as an etch mask for producing trenches in the silicon that can be filled with new materials to achieve a planar structure.
Applications:
Nanowires show promise for use in applications including:
• Exceptionally small electronic circuits
• Memory devices
• Transistors
• Advanced composite materials
• Quantum devices
• Biomolecular nanosensors
• MEMS
• Optoelectronics
• Field Emitters
• Photon Ballistic Waveguides
The goal of this project is the design of artificial materials that consist of ultrafine wires or linear arrays of dots, ten to hundred times finer than those produced with commercial micro-structure fabrication techniques. In fact, we have gone all the way down to atom chains which may be viewed as the ultimate nanowires (scroll to the bottom for those). These patterns are formed by self-assembly, where atoms arrange themselves naturally at stepped silicon surfaces.
An important aspect in fabricating nanowires is the ability to prepare wires of an any material on any substrate with any thickness. In particular, using silicon wafers as substrate is highly-desirable. To achieve this goal we suggest the following "universal" process. First, a silicon substrate with a regular array of steps is prepared (A). Then, stripes (B) or dots (C) of a passivating material are attached to the step edges. This part is analogous to creating a photoresist mask in traditional lithography. As mask material we use calcium fluoride, which is lattice-matched to silicon and chemically inert. Eventually, the desired material is deposited on the remaining silicon, for example by substrate-selective chemical vapor deposition (CVD) or electroplating. Alternatively, calcium fluoride could become useful as an etch mask for producing trenches in the silicon that can be filled with new materials to achieve a planar structure.
Applications:
Nanowires show promise for use in applications including:
• Exceptionally small electronic circuits
• Memory devices
• Transistors
• Advanced composite materials
• Quantum devices
• Biomolecular nanosensors
• MEMS
• Optoelectronics
• Field Emitters
• Photon Ballistic Waveguides