The objectives of this research are to pattern one-dimensional (1D) periodic nanostructures directly on free-standing nanowires (NWs), demonstrate rudimentary control of the grating periods, and investigate their suitability as on-wire optical grating. This technique is based on our recently discovered laser-driven self-assembly process: by gently focusing a near-UV femtosecond laser beam onto substrates in an atmosphere containing tungsten hexacarbonyl, 1D array of tungsten nanostructure forms spontaneously on almost any materials. Tungsten nanograting (TNG) with excellent long-range order can be obtained by scanning the substrates across the laser beam.
The Intellectual Merits of this research lie in the fact that our technique is potentially a single-step, single-beam, room-temperature, and dry process to pattern gratings directly on free-standing NWs. On-wire nanograting is expected to become a fundamental building block for NW-based nanophotonics. However, NWs are increasingly sensitive to the chemical contamination in conventional lithography due to their small dimensions. Our method, on the other hand, involves only single step and therefore could preserve their chemical and physical integrity.
Broader Impacts: TNG as on-wire optical grating could enable a host of new applications in NW-based active nanophotonics such as lasers, chemical and mechanical sensors. Graduate and undergraduate students involved in this project will have opportunity to carry out cutting-edge research in femtosecond laser nanofabrication. Besides, we will offer high-school students summer research opportunity to participate in this project under supervision of graduate students in our laboratory and to expose them to the emerging field of nanoscience and technology.
