Multilayered nanostructures: production and applications — P. Tsygankov
6 Dec 2012
Petr Tsygankov, Ph.D., the head of “New matherials” laboratory
The history of industrial use of nanolayered structures began in 1938 when Katherine Blodgett, talented co-worker of Irving Langmuir invented and implemented a method of deposition of multilayer thin and monatomic films on solid substrates. This is how the “low-reflectance optics” has been developed, without which any optical equipment today is unthinkable. Clear competitive advantages provided by multilayer coatings have led to “explosive” development of the technology of thin films and the production of the corresponding equipment. Modern technology of optical coatings employs metal-dielectric layered systems (instead of organic) and thermal-vacuum equipment for their production.
This development allowed Richard Feynman to point out in his famous speech in 1959 that the technology of thin films is one of the few technologies of “nanoworld” that has been successfully developed by mankind. Today, multilayer optics industry has an annual turnover of tens of billions of dollars, and optical coatings operating in the range from thermal radiation to the vacuum ultraviolet are broadly used.
Progress in the development of thermo-vacuum equipment for the thin multilayer film manufacturing provided another qualitative leap – the production of heterostructures. We have learned how to model and use the technology of molecular beam epitaxy (MBE), to create materials with desired properties of the electron bands. As the result, now one can put a cell phone in a pocket, a small LED flashlight emits ultraviolet, and we witness the widespread replacement of inefficient incandescent sources with LED.
Since the 70’s of the last century, the vacuum ion-plasma equipment began to be widely spread in the industry, providing active influence on the process of film formation and management of film properties. It became possible to create multi-layered structures consisting of thin homogeneous layers with a thickness of a few atomic periods made of dissimilar materials – the so-called artificially modulated structures. During the last decade, the effect of giant magnetoresistance (GMR) discovered in these structures in 1989 has led to a sharp increase in the density of magnetic recording – the hard disk capacitance has increased by several orders of magnitude, up to terabytes.
In my lecture I will present a historical review about the development of technologies for production of multilayer structures based on thin films and monoatomic layers. The focus will be made on basic principles of production of multilayer films by vacuum thermal evaporation, molecular beam epitaxy, and ion-plasma methods. I will demonstrate fascinating properties of these materials and show that we are only at the beginning of their studies.