18 Jul '17
Scientists at the Tomsk State University (TSU) in Siberia have pioneered the growing of semiconductors from organic molecules in the gas phase in Russia. Their super-thin films are reported to be 5,000 thinner than a human hair.
The self-assembly of molecules is said to have led to the emergence of semiconductor structures that provide increased speed of devices with minimal energy costs, thus paving the way for the development of a new family of molecular nanoelectronics.
“The main technical problem of producing devices based on organic semiconductors created by traditional methods of sputtering is that they have low conductivity, because individual molecules interact poorly with each other. Overcoming this barrier is possible with the help of molecular epitaxy, a method of layer-by-layer application which provides chemical binding of molecules and thereby increases charge transport,” said Tatyana Kopylova of TSU’s Laboratory of Organic Electronics.
“The self-assembly reaction of molecules is carried out in the gas phase. This significantly expands the choice of materials for the production of semiconductors, because you can evaporate almost any low-molecular substance. The cultivation of one monolayer takes 15-30 minutes, which enables us to design semiconductors of any complexity. For comparison: in classical technologies, where molecules are applied through the dissolution of a substance, the formation of one layer on the carrier takes three days,” explained Vladimir Burtman, a researcher and professor at TSU and the University of Utah.
It is expected that semiconductors made by molecular epitaxy will demonstrate a considerable drop in power consumption and an exponential growth of speed.
The new Siberian technology is effectively addressing a deep-rooted snag thwarting many efforts in molecular electronics and nanoelectronics. Typically, all devices that have organic conducting materials gradually decompose with time, compromised by load and temperature. The new discovery makes it possible to form very strong bonds between molecules, which is expected to significantly extend the service life of equipment.
The developers believe such equipment will have increased functionality at a much reduced cost. Making new organic semiconductors does not require extremely high temperatures—heating to 300-400 degrees Celsius is enough, just half of what nonorganic semiconductors require.