Electronic logic gates from three-segment nanowires featuring two p–n heterojunctions

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We report a novel nanodevice using π-conjugated polymers and inorganic semiconductor dual composite P–N junctions single nanowire constructed by PEDOT–PbS–PPY (EPP) nanowire as a two-input OR gate. The nanodevices logic gate may show some key value in nanoelectronic components. A team led by Yuliang Li from Beijing, China, has assembled three different semiconductors into a single nanowire that comprises two p-n heterojunctions and acts as an electronic logic gate. Such heterojunctions — the interfaces between p- and n-type semiconductors — are crucial components of a variety of electronic devices. The researchers constructed the nanowire through a process of electrochemical deposition and template-directed growth, placing an n-type inorganic material — lead sulphide (PbS) — between two p-type organic materials, the π-conjugated polymers poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy). In the resulting three-section nanowire, each junction (PEDOT/PbS and PPy/PbS) acts as a diode, only transporting current towards the central PbS rod. When the organic segments are subjected to a voltage input, and the inorganic segment serves as output, the device acts as an ‘or’ logic gate where a non-zero voltage in either, or both, inputs provides a non-zero output. A novel heterojunction structure combining three kinds of semiconductors was designed and fabricated. The heterojunction structure can be used as a two-input OR gate with the combination of two diodes on the two interfaces of the organic/inorganic semiconductor. The research will have great influence in both the fundamental research field of nanoscience and the device application field of nanotechnology.