Shape-Controlled Growth of Nanostructured Films and Objects

Technology #11960

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FIGS. 4A and 4B shows placement of a cap substrate on top of a substrate on which nanostructures grow, where the flow through the cap substrate is pre-treated by contact with suitable materials arranged on the surfaces of the capFIGS. 6A, 6B and 6C shows placement of a template cap substrate on top of a substrate on which nanostructures grow, where the cap is textured so that the nanostructures can grow to fill the cavities between the growth substrate and the cap substrate; free-standing forms of nanostructures on the growth substrate of after removal of the template; and free-standing forms of nanostructures after removal of the template and the growth substrate;FIGS. 10A and 10B shows use of a film of nanostructures as an interface material during rotary motion between a shaft and a housing
Categories
Inventors
Professor John Hart
Department of Mechanical Engineering, MIT
External Link (mechanosynthesis.mit.edu)
Professor Alex Slocum
Department of Mechanical Engineering, MIT
External Link (pergatory.mit.edu)
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

Shape controlled growth of nanostructured films and objects

US Patent 7,976,815
Publications
Force Output, Control of Film Structure, and Microscale Shape Transfer by Carbon Nanotube Growth under Mechanical Pressure
Nano Lett., 2006, 6 (6), pp 1254–1260

Applications

The technology described in this invention can be used to create nanostructures with specific geometry for a wide range of applications, including thermal or electrical contact elements in NEMS, field emitter arrays, or scaffolds for growth of biological materials.

Problem Addressed

Carbon nanotubes (CNTs) and other nanomaterials are typically grown as thin films using chemical vapor deposition (CVD). This process allows significant control over the 2D geometry of the resulting thin films by patterning of the catalyst layer used to promote growth. However, methods to achieve specific 3D geometries in CVD-grown nanostructures remain limited. This invention provides a method to control the growth of nanostructured films and objects to achieve specific geometry using a template facing the growth substrate.

Technology

A secondary “cap” substrate is fabricated with predefined surface topography and placed on top of the primary growth substrate, forming a growth cavity in between the two substrate surfaces. During the CVD process, the growth of nanostructures is constrained to this cavity, producing nanostructured films with shape complementary to the cavity. The cap substrate may be further modified to provide further control over the growth process. For example, holes, pores, or microchannels may be used in the cap substrate to allow targeted delivery of reaction species specific growth regions. In addition, force could be applied to the growing nanostructured film either mechanically using refractory bolts or electrically via a potential difference between cap and growth substrates.

Not only does this process allow nanostructures to be grown in a variety of shapes, it is also generally applicable to a wide range of materials such as CNTs, silicon nanowires, and silicon carbide nanotubes. After the growth process, the resulting nanostructures can undergo a range of post-processing steps including impregnation with polymers to create composite materials and release from the substrate for use in larger assemblies.

Advantages

  • Provides control over 3D geometry of nanostructured films
  • Applicable to a wide range of CVD-grown nanomaterials