Nanopatterning refers to the fabrication of nanometer-scale structures, meaning patterns with at least one lateral dimension between the size of an individual atom and approximately 100 nm. Direct Write or Maskless Lithography as discussed in this article refers to the use of a focused beam, either an ion beam or an electron beam, to create a patterned image directly into (etch), or on top of (deposition), the target material. Both electron beams and ion beams can be used together with gas injection technology to deposit three dimensional structures on the nanometer scale through the process of either electron beam assisted or ion beam assisted chemical vapor deposition (CVD). The deposition occurs only in the vicinity where the electron beam or ion beam is being scanned. Therefore, the deposit will follow the form of the scanned beam in two dimensions. This approach can be applied to produce three-dimensional objects by successively layering upon the two-dimensional pattern. In the case of ion beams in particular, the direct write process can also produce an etch pattern on the nanometer scale as the ion beam physically mills away the material via ion bombardment. This process can also be chemically enhanced for certain materials such as simultaneous use of water to selectively etch carbon.