Methods of top-down nanofabrication enable creation of complex micro and nanostructures known as MEMS and NEMS. For example, techniques for creating TDTR or BLS samples typically include electron-beam lithography (EBL), photolithography, physical vapour deposition (PVD) of metals, reactive ion etching (RIE), wet and vapour etching, as well as other minor clean room methods of sample treatment. An example process flow for a typical TDTR sample is shown in the figure below:
Scanning electron images below show the example of the suspended nanostructures fabricated using top-down nanofabrication methods. The examples include nanowires, nanobeams, and various phononic crystals.