DNA transistors
Carbon transistors grown on DNA strands
Anatoly Sokolov, an employee of Stanford University, together with fellow physicists, developed a method for producing carbon transistors based on DNA strands. The description of the method is published in Nature Communications (Sokolov et al., Direct growth of aligned graphitic nanoribbons from a DNA template by chemical vapour deposition), the content of the article is briefly retold on the website of Stanford School of Engineering (Stanford Scientists Use DNA to Assemble a Transistor From Graphene).
During the experiment, bacterial DNA was applied to a silicon substrate, where the nucleic acid was stretched into almost straight straight strands. Then the DNA substrate was transferred to a sealed chamber with methane and heated. From the action of heat, some of the carbon atoms were released from the DNA (in fact, the DNA on the substrate was charred). Methane molecules were attached to such atoms from, forming thin carbon strips on the substrate.
The aim of the scientists' work was to use DNA as a guiding structure for growing thin (several atoms wide, up to 10 nanometers) graphene strips. As it was shown earlier, such strips, unlike graphene sheets, are semiconductors, therefore they can be used to create transistors. According to the authors, depending on the production conditions, they produced either metallic or semiconductor carbon nanowires. The carbon in them, however, was in different electronic states in different places and resembled graphite rather than graphene. Nevertheless, the authors hope that in the future it will be possible to obtain pure graphene transistors by this method.
Physicists have learned to give graphene the properties of a semiconductor without using DNA. To do this, you can superimpose a sheet of monatomic carbon on another flat monatomic material, for example, boron nitride. In addition, graphene researchers have recently learned how to cut it into fragments of the desired shape using a laser and stack them in stacks where the material can form van der Waals heterostructures.
Portal "Eternal youth" http://vechnayamolodost.ru09.09.2013