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