Ohmic‐Contact‐Gated Carbon Nanotube Transistors for High‐Performance Analog Amplifiers

The growing demand for ubiquitous data collection has driven the development of sensing technologies with local data processing. As a result, solution‐processed semiconductors are widely employed due to their compatibility with low‐cost additive manufacturing on a wide range of substrates. However, to fully realize their potential in sensing applications, high‐performance scalable analog amplifiers must be realized. Here, ohmic‐contact‐gated transistors (OCGTs) based on solution‐processed semiconducting single‐walled carbon nanotubes are introduced to address this unmet need. This new device concept enables output current saturation in the short‐channel limit without compromising output current drive. The resulting OCGTs are used in common‐source amplifiers to achieve the highest width‐normalized output current (≈30 µA µm–1) and length‐scaled signal gain (≈230 µm–1) to date for solution‐processed semiconductors. The utility of these amplifiers for emerging sensing technologies is demonstrated by the amplification of complex millivolt‐scale analog biological signals including the outputs of electromyography, photoplethysmogram, and accelerometer sensors. Since the OCGT design is compatible with other solution‐processed semiconducting materials, this work establishes a general route to high‐performance, solution‐processed analog electronics. Increasing demand for small‐signal biological sensing applications requires improved low‐power, high‐performance, solution‐processed analog amplifiers. To achieve this goal, a novel ohmic‐contact‐gated transistor is introduced and demonstrated for solution‐processed semiconducting single‐walled carbon nanotubes. These devices achieve the highest reported combination of channel‐width‐normalized drive current and channel‐length‐normalized signal gain, resulting in analog amplifiers that are well‐suited for biological and physiological signals.