Milestone for Plasmonics: The Plasmon Generating Transistor

• Simple design
• Direct conversion of electronic to plasmonic information
• Reliable
• Based on single quantum systems like molecules
• Central building block for implementation of plasmonics in modern computation

• Plasmonic circuits
• Junction between electronics and plasmonics

The invention of the transistor sparked the outstanding development towards modern electronics. Nevertheless, the continuous miniaturization of transistors towards nanometer scales is prospected to stop within this decade as heat deposition becomes a major problem in smaller devices. Though, thermal heat can be significantly reduced by use of plasmonic circuits. These employ photon-like electromagnetic excitations localized on bulk solids – called plasmons, which can carry information in the same way as electric currents in classical electronics. However, implementation of plasmonic circuits requires fundamental building blocks for coupling of electronic and plasmonic circuits that have not yet been developed.

A novel transistor concept has been developed to overcome the aforementioned shortcoming that is capable of converting an electric current to plasmons and vice versa. The embodiment of this invention as shown in figure 1 consists of a single quantum system (i.e. a molecule) located in a double tunnel barrier between two electrodes. By varying the space between drain and the molecule d_vac, the gate voltage U_G and the electric field E can be changed and optimized independently from the tunnel voltage. Above a specific field strength, electrons tunneling through the junction excite surface plasmon polariton (SPP) that are either radiated as light or they propagate along the electrode surface. By varying the bias voltage applied to the electrodes, the Fermi level of one electrode shifts in resonance with the lowest unoccupied state of the quantum system raising both a significantly increased tunnel current and an increased emission of plasmons. Integrated as junctions between electronic and plasmonic circuits such transistors convert electronic information (voltage/current) into information carried by plasmons and vice versa. As a key technology, they are essential building blocks for embedding plasmonics into future electronics.  

PCT (WO2015082343A1), USPTO (US10134498B2)

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