Two- and three-terminal molecular electronic devices with ballistic electron

Highlights

Molecular electronics makes use of molecules as circuit elements. This new type of electronic component enables the possibility of extremely small devices and offers the prospect of a wider range of function than conventional semiconductors. These advantages stem from the unique transport mechanisms involved in nanoscale molecular transport, including ballistic transport. Ballistic carriers (electrons or holes) travel without scattering, and have excess energy relative to their surroundings. These features can be used to achieve desirable functions, including high-speed operation, chemical reactions, and excitation of light emission.

This innovation offers the design of two- or three- terminal molecular electronic devices with ballistic transport. In all embodiments, ballistic transport can occur within a unique junction design based on carbon-carbon bonding between the substrate and the molecular layer, the latter of which can be a wide range of structures. This paradigm facilitates a large array of electronic behaviour possibilities in a robust package that is commercially viable.

Technology transfer

This technology is available for licensing, or for further development through a collaborative research agreement with the National Research Council of Canada (NRC). The business opportunity may be referred to by its NRC ID: 2010-063-04.

Market applications

Areas of application include microelectronics, computing, imaging and display technology, and chemical sensing. For example, ballistic carriers may be capable of exciting luminescence to generate light in an efficient and colour tunable fashion, providing a unique photonic or display technology. Market applications of this innovation include resonant tunneling diodes, gated operations, high-frequency switching, logic circuits, light emitting devices, chemical detection, and materials characterization.

How it works

The two-terminal molecular junction consists of a molecular layer between two conductors, such that a nanoscale sandwich is formed in a conductor-molecule-conductor junction format. The total thickness of the molecular layer is less than or approximately equal to the mean free path of a charge carrier travelling through the device. Some fraction of carriers travel ballistically through the molecule and into the second conductor. This enables the charge carriers to maintain excess energy relative to the surrounding non-ballistic carriers, and it is this energy that can be used to perform functions such as light emission or chemical reactions.

The three-terminal molecular electronic device consists of two molecular junctions arranged in series such that a stacked of conductor-molecule-conductor-molecule-conductor junction results with each conductor functioning as a separate electrode. The total thickness of all layers can be less than or approximately equal to the mean free path of a carrier in the layers. Ballistic transport can occur for some fraction of a plurality of carriers in the three layers, with the resulting device acting like a vacuum tube triode. The materials that are used for the two different molecular layers can be optimized to achieve a desired effect, such as high transconductance in a transistor or resonant tunneling by matching of appropriate energy levels (i.e., as a molecular Esaki diode).

Benefits

This innovation uses molecular layers to build electronic devices, which is distinct from current device designs, and entails a larger number of materials in the devices. Increasing the energy levels of the materials can lead to a wider range of functions and fine-tuning of the device for specific applications. In addition, by making use of the nanoscale transport in the ballistic regime, the generation of heat is confined to areas outside of the active element of the devices, potentially both reducing heat waste and making heat management easier. Ballistic devices operate with much lower power consumption than conventional resistors and transistors. Low voltage and low power operations may greatly extend battery life and conserve energy. Finally, because molecular structures are already incorporated into commercial devices, any unique and valuable electronic properties displayed by these devices can be made in a way that is compatible with commercial processing and materials.