Nanoscopic wire-based devices and arrays

Abstract

Electrical devices comprised of nanoscopic wires are described, along with methods of their manufacture and use. The nanoscopic wires can be nanotubes, preferably single-walled carbon nanotubes. They can be arranged in crossbar arrays using chemically patterned surfaces for direction, via chemical vapor deposition. Chemical vapor deposition also can be used to form nanotubes in arrays in the presence of directing electric fields, optionally in combination with self-assembled monolayer patterns. Bistable devices are described.

1 - 23 . (canceled)  
     
     
         24 . A method comprising: 
 forming a nanoscopic wire on a surface in a pattern dictated by chemically patterned surface.    
     
     
         25 . A method as in  claim 24 , wherein the patterned surface includes a first portion of a first chemical functionality adjacent a second portion of a second, different chemical functionality.  
     
     
         26 . A method as in  claim 25 , wherein at least one of the first portion and the second portion is defined by a self-assembled monolayer.  
     
     
         27 . A method as in  claim 24 , wherein the nanoscopic wire is a pre-formed wire, the method comprising applying the pre-formed nanoscopic wire to the surface in the pattern.  
     
     
         28 . A method as in  claim 24 , comprising growing the nanoscopic wire on the surface in the pattern.  
     
     
         29 . A method as in  claim 24 , wherein the pattern comprises a plurality of catalytic colloid sites.  
     
     
         30 . A method as in  claim 24 , wherein the pattern comprises a micro-phase separated block copolymer structure.  
     
     
         31 . A method comprising: 
 growing a nanoscopic wire in the presence of an electric field of intensity sufficient to orient the growth of the wire.    
     
     
         32 . A method as in  claim 31 , comprising growing the nanoscopic wire via CVD.  
     
     
         33 . A method as in  claim 31 , comprising providing a catalytic site, creating the electric field oriented in a predetermined direction relative to the catalytic site, and growing the nanoscopic wire catalytically from the site in the predetermined direction.  
     
     
         34 . A method comprising: 
 forming a nanoscopic wire on a surface in a pattern dictated by a mechanically patterned surface.    
     
     
         35 . A method as in  claim 34 , wherein the step of forming comprises inscribing a trench in the surface.  
     
     
         36 . A method as in  claim 35 , wherein the nanoscopic wire is formed in the trench.  
     
     
         37 . A method as in  claim 34 , wherein the step of forming comprises providing an article having a plurality of indentations and protrusions, and positioning the plurality of protrusions in contact with the surface so as to form cavities defined by the surface and the plurality of indentations.  
     
     
         38 . A method as in  claim 37 , wherein the cavities comprise capillaries.  
     
     
         39 . A method comprising: 
 forming a nanoscopic wire on a surface in a pattern dictated by gas flow.    
     
     
         40 . A method as in  claim 39 , wherein the gas flow comprises reactants for the nanoscopic wire.  
     
     
         41 . A method comprising: 
 providing a crossbar array comprising at least two wires in crossbar array orientation, the wires being free of contact with each other; and    bringing the wires into contact with each other.    
     
     
         42 . A method as in  claim 41 , wherein the crossbar array includes at least one nanoscopic wire.  
     
     
         43 . A method as in  claim 41 , wherein the at least two wires comprise a first wire disposed adjacent a second wire at a junction.  
     
     
         44 . A method as in  claim 43 , wherein the wires are brought into electrical contact with each other at the junction.  
     
     
         45 . A method as in  claim 43 , wherein the wires are brought into van der Waals contact with each other at the junction.  
     
     
         46 . A method as in  claim 45 , wherein the step of bringing the wires into contact with each other comprises deforming the second wire.  
     
     
         47 . A method as in  claim 43 , wherein the first and second wires are brought into contact by applying a stimulus to at least the second wire.  
     
     
         48 . A method as in  claim 47 , wherein the stimulus comprises biasing the first and second wires with opposite polarity.  
     
     
         49 . A method as in  claim 47 , wherein the first and second wires maintain contact upon removal of the stimulus.  
     
     
         50 . A method as in  claim 43 , further comprising releasing the wires from contact with each other.  
     
     
         51 . A method as in  claim 50 , wherein the step of releasing comprises applying a stimulus to at least the second wire.  
     
     
         52 . A method as in  claim 51 , wherein the stimulus comprises biasing the first and second wires with the same polarity.  
     
     
         53 . A method as in  claim 41 , further comprising releasing the wires from contact with each other.  
     
     
         54 . A method as in  claim 53 , wherein each of the steps of bringing the wires into contact and releasing the wires from contact comprises a switching step.  
     
     
         55 - 59 . (canceled)  
     
     
         60 . A method comprising: 
 switching a memory element of a crossbar array between “on” and “off” states by alternatively biasing, at similar and opposite polarity, wires that cross in the array to define the element.    
     
     
         61 . A method as in  claim 60 , comprising biasing the wires that cross to form the element from locations remote from the element.  
     
     
         62 . A method as in  claim 60 , comprising switching the element between “on” and “off” states by bringing wires that cross in the array to form the memory element alternately into contact with each other and removing them from contact with each other.  
     
     
         63 - 77 . (canceled)  
     
     
         78 . A method comprising: 
 providing a mixture of metallic nanotubes and semiconducting nanotubes; and    separating the metallic nanotubes from the semiconducting nanotubes.    
     
     
         79 . A method as in  claim 78 , wherein the step of separating comprises subjecting the mixture to an electric field of intensity sufficient to selectively orient metallic nanotubes.  
     
     
         80 . A method as in  claim 79 , wherein the electric field is of an intensity such that semiconducting nanotubes remain unoriented with respect to the electric field.  
     
     
         81 - 89 . (canceled)