Fractional Quantum Hall Effect in Organic Molecular Semiconductors
30 June 2000
High quality crystals of the organic molecular semiconductors tetracene and pentacene are used to prepare metal-oxide-semiconductor (MOS) structures exhibiting hole as well as electron mobilities exceeding 10 sup 4 square centimeter per volt per second. The carrier concentration in the channel region of these ambipolar field-effect devices is controlled by the applied gate-voltage.
Well-defined Shubnikov- de Haas oscillations and quantized Hall plateaus are observed for two-dimensional carrier densities in the range of 10 sup (11) per square centimeter. Moreover, fractional Quantum Hall states are observed in tetracene crystals at temperatures as high as ~2 Kelvin.