Chinese scientists pursuing nano technology demonstrate a laser solution to make thin structures using inexpensive, pinpoint accuracy in the creation of nanostructures on gold nanofilms.

Xi'an Jiaotong University scientists have successfully achieved a breakthrough in nano technology by creating a new mode of directly writing nanostructures on gold nano-films in a laser-irradiated scanning near-field optical microscope (SNOM) probe tip. Under the supervision of the two authors, namely Xuesong Mei and Jianlei Cui, the work of the group focuses on a problem that has lingered in nano technology: optical limitation.

Unconventional methods such as electron beam lithography and optical lithography have restrictions on the use of metal nanofilms and their feature sizes. This new technology applies a nanosecond laser with a nanosecond microsphere lens which is concentrated by the probe of an instrument known as SNOM to allow near-micron-scale writing without the application of masking or vacuum conditions.

The team managed to obtain an impressive minimum linewidth of 83.6 nm with consistencies of about 167.8 +/- 6.6 nm on average. Energy dispersive spectrometer analysis of the process showed it involved melting the Au nanofilm with locally excited surface plasmon polaritons (SPPs), which provided a nanoscale energy scale for high-resolution fabrication.

This nano technology improvement heralds a new world in nanolithography and in general nano welding of different materials. The method has potential in industrial and academic use because of its low costs and maskless production.