Patent ID: 7473436

Claim:
A method for functionalizing a collection of carbon nanotubes (CNTs), the method comprising: irradiating a precursor gas at a selected production location to provide a plurality of particles of a selected charged particle target species in a first chamber having a first selected chamber pressure p 1 , and to provide a preferred initial velocity for at least one particle of the selected charged particle target species, where at least one charged non-target species particle is also present in the first chamber; providing a collection of CNTs on a substrate in a second chamber having a second selected sub-Torr pressure p 2 , where p 2 lies in a range of about 0.002·p 1 –0.01·p 1 ; providing a particle communication mechanism, having a particle aperture entrance that is spaced apart from the production location by a selected distance, that allows transport of at least a portion of the particles from the first chamber to the second chamber; configuring the particle communication mechanism so that transport of ultraviolet radiation from said first chamber to said second chamber is suppressed; providing a substantially constant vector magnetic field B in the first chamber, where the magnitude and direction of the magnetic field B are chosen so that (i) a trajectory in the field B of at least one particle of the selected charged particle target species produced at the production location will pass substantially through the aperture entrance and (ii) a trajectory in the field B for at least one charged non-target species particle produced at the production location will be no closer than a positive threshold distance from the aperture entrance, whereby at least one particle of the selected charged particle target species becomes chemically attached to at least one of the CNTs in the second chamber, and a density of the at least one non-target species adjacent to the aperture entrance is reduced relative to a density of the selected charged particle target species adjacent to the aperture entrance.