Fabrication of 3D phononic crystals using colloidal crystallization

We are also working on fabricating three-dimensional periodic nanoscale structures using colloidal maasilta2.jpegcrystallization of polymeric nanospheres, for use as phononic structures to control heat transport. Thick and large crystals have been successfully deposited in a single-step vertical dipping process [Isotalo2014]. We have recently also succeeded in depositing micron-scale metal wires on top of the polymer structures using e-beam lithography and direct 3D laser writing [Tian2017], paving the way for real device applications. The success was made possible by electron-beam induced cross-linking of the deposited colloidal crystal before exposing it to the harsh chemicals used in the following lithography steps.