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Monolithically Integrated Flexible Black Phosphorus Complementary Inverter Circuits

TitleMonolithically Integrated Flexible Black Phosphorus Complementary Inverter Circuits
Publication TypeJournal Article
Year of Publication2017
AuthorsLiu, Yuanda, and Ang Kah-Wee
JournalACS Nano
Date Published07/2017
Keywords1st-principles, black phosphorus, complementary, contacts, electronics, field-effect transistors, flexible, graphene, hexagonal boron-nitride, inverter, monolithic integrated, mos2 transistors, performance, robust, transition

Two-dimensional (2D) inverters are a fundamental building block for flexible logic circuits which have previously been realized by heterogeneously wiring transistors with two discrete channel materials. Here, we demonstrate a monolithically integrated complementary inverter made using a homogeneous black phosphorus (BP) nanosheet on flexible substrates. The digital logic inverter circuit is demonstrated via effective threshold voltage tuning within a single BP material, which offers both electron and hole dominated conducting channels with nearly symmetric pinch-off and current saturation. Controllable electron concentration is achieved by accurately modulating the aluminum (Al) donor doping, which realizes BP n-FET with a room-temperature on/off ratio {\textgreater}10(3). Simultaneously, work function engineering is employed to obtain a low Schottky barrier contact electrode that facilities hole injection, thus enhancing the current density of the BP p-FET by 9.4 times. The flexible inverter circuit shows a clear digital logic voltage inversion operation along with a larger-than-unity direct current voltage gain, while exhibits alternating current dynamic signal switching at a record high frequency up to 100 kHz and remarkable electrical stability upon mechanical bending with a radii as small as 4 mm. Our study demonstrates a practical monolithic integration strategy for achieving functional logic circuits on one material platform, paving the way for future high-density flexible electronic applications.


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