IBM inventors Ali Afzali-Ardakani and Praveen Chaudhari have devised a molecular manipulator that can controllably grasp a nanostructure, move the nanostructure by moving a probe such as a scanned-proximity probe microscope to a predetermined location, and controllably release the grasped nanostructure at a desired position. The molecular manipulators, which resemble tiny tweezers and clamps, may be used to repair a circuit, which contains nanoparticles as components, or to construct a nanostructure which cannot be fabricated by conventional lithographic processes.
In U.S. Patent Application 20090313731, the IBM researchers describe how to make various molecular synthetic receptors that act as tweezers or clips to grasp and release molecular substrates. The molecular manipulator is made of a light-sensitive molecule, including a double bond that changes its cis-trans configuration in response to illumination by a selected wavelength of light, and a probe, such as an atomic force microscope (AFM), to which the light-sensitive molecule may be attached.
The method of making the molecular scale manipulator includes covalently bonding a light-sensitive molecule, which may grasp a nanostructure upon illumination by a first wavelength of light and release the nanostructure upon illumination by a second wavelength of light, to a probe, such as a scanned-proximity probe microscope.
The method of making the molecular scale manipulator includes covalently bonding a light-sensitive molecule, which may grasp a nanostructure upon illumination by a first wavelength of light and release the nanostructure upon illumination by a second wavelength of light, to a probe, such as a scanned-proximity probe microscope.
A method of moving a selected nanostructure includes bringing the light-sensitive molecule in proximity to a selected nanostructure by moving a probe, for example, a probe of a scanned-proximity probe microscope, to which the light-sensitive molecule may be attached, in proximity to the selected nanostructure, controllably grasping the selected nanostructure by illuminating the light-sensitive molecule with a first wavelength of light, moving the selected nanostructure to a predetermined position by moving the probe to the predetermined position, and releasing the selected nanostructure by illuminating the light-sensitive molecule with a second wavelength of light.
The position of the tip relative to a reference coordinate of the sample surface can be controlled by piezoceramic controllers, which allow three-dimensional positioning with great accuracy and precision. In the AFM, a feedback circuit can maintain the tip at a constant height in the z direction from the sample surface, as the tip is scanned over the sample surface in the x and y directions.
FIG. 1A illustrates a light-sensitive molecule (100), opened and closed, which includes two azo double bonds, in an example of IBM’s molecular manipulator. Each arm of the light-sensitive molecule may be bonded at a first end to the moiety (130) and at a second end to a functional group (R), which may include, for example, alkyls, haloalkyls, aryls, alcohols, ethers, amines, aldehydes, ketones, carboxylic acids, esters, and amides. In other examples, the functional group (R) at the second end of each arm may be the same or different in the two arms (110). The spacing between the two arms may be varied by using various functional groups.
FIG. 2 illustrates a molecular manipulator (200) that includes the light-sensitive molecule of FIG. 1A and a probe (230), for example, a probe of a scanned-proximity probe microscope, to which the light-sensitive molecule is attached. FIG. 1B illustrates a light-sensitive molecule (100), which includes a single azo double bond, in an example of a molecular manipulator.
FIG. 3 illustrates a flowchart (300) of a method of making the molecular manipulator of FIG. 2. which comprises covalently bonding (310) to a probe, a light-sensitive molecule that changes a cis-trans configuration of a double bond in response to light of a selected wavelength.
FIG. 4 illustrates a flowchart (400) of a method of moving a nanostructure with the molecular manipulator of FIG. 2
The method of moving a nanostructure includes grasping (440) the nanostructure with a light-sensitive molecule, which is attached to a probe, for example, a probe of a scanned-proximity probe microscope, by illuminating the light-sensitive molecule with a first wavelength of light to change a double bond from a trans configuration to a cis configuration within the light-sensitive molecule, moving (460) the grasped nanostructure to a predetermined position by moving the probe to a predetermined location, and releasing (480) the nanostructure from the light-sensitive molecule by illuminating the light-sensitive molecule with a second wavelength of light to change the double bond from the cis configuration to the trans configuration. Moving a probe of a scanned-proximity probe microscope, into proximity with the nanostructure may be accomplished by using the tip of a probe in an AFM mode.
