Reconfigurable Flexible Complementary Circuits Based on Polarity-Configurable Carbon Nanotube Transistors

Functional configurability is highly desired for flexible electronics to serve ever-changing and diverse application scenarios. In complementary metal-oxide-semiconductor (CMOS) logic circuits, functional configurations can be achieved at the most basic device level by modulating the P/N polarity of the field-effect transistors. The intrinsic ambipolarity of low-dimensional materials provides the possibility of configuring the polarity of the constructed transistors by selectively injecting carriers on demand with proper methodologies. In this study, we propose a strategy based on carbon nanotubes (CNTs), with the initial devices functioning as conventional p-type thin film transistors (TFTs), that achieves polarity configuration through reversible electrostatic doping by applying and removing a polymer doping layer on the channel area covered with a Y₂O₃ passivation layer. This method exhibits favorable characteristics, including high performance comparable to those of conventional devices under normal operation conditions, good P/N symmetry, large-scale uniformity, nonvolatile features, and robust stability. The resultant configurable TFTs facilitate the construction of a CMOS inverter with a rail-to-rail output and a high voltage gain exceeding 40. Basic circuit components such as diodes, rectifiers, and logic gates are constructed with reconfigurable functionalities. To illustrate its potential, we designed a reconfigurable CMOS circuit module that can be optionally programmed into four different functions─NAND, NOR, XOR, and XNOR, which can serve as a building block for constructing more complex reconfigurable integrated circuits, applicable in fields such as hardware security and adaptive monitoring.