photographist

“The Sun is a very highly ionized plasma, a hot plasma. Plasmas are ionised gases, regarded as the fourth state of matter. Today, everyone knows plasma TVs that are weakly ionized plasmas. In these plasmas, some years ago I was studying the different internal energy modes of the molecules - electronic, vibration, rotation-and energy transfer that can occur between these modes. One of the interesting applications was the recombination of nitrogen atoms on the walls to mimic what happens when a space shuttle enters the atmosphere. The plasma surface treatment (another application) allows working at a lower surface temperature than conventional treatments which makes it possible treatment or thin film deposition on temperature-sensitive materials like polymers but also silicon layers for photovoltaic industry . Plasmas led me to new fields of research : diamond growth by plasma!

Natural diamonds grow in the depths of the earth at very high pressure and temperature. In the 50s, Percy W. Bridgman had postulated the possibility of growing diamond under conditions of low pressure and this was demonstrated in 1956 by American and Russian teams. Later on, in the 80s, Japanese researchers had the idea of using plasmas to create an atmosphere rich in atomic hydrogen near the surface on which diamond could grow. Today my laboratory is at the international cutting edge both for growing ultra pure single diamond crystal and for a deep understanding of the plasmas suitable for diamond growth. The diamond has many applications, both in optics, mechanics, electronics ... and one of the Holy Grails for us is the application in power electronics, since diamond could be the only material to make switches holding voltages of the order of 20,000 volts. However, work is still progress to be done for that.”

Alix Gicquel
Professor, LSPM, CNRS, University of Paris 13

next