Highly Sensitive Pressure Sensor Based on Tunneling Effect in Suspended G/h-BN/G Heterostructure Membrane

Gas pressure sensors play a crucial role in the area of aerospace, national defense and military, human health and medical care. The traditional silicon-based piezoresistive sensors, however, struggle with the trade-off between sensitivity and the size of the sensing membrane, which limits their applications in ultra-miniaturized devices. Herein, we have detailed the stress-sensitive effect of tunneling current in the graphene/hexagonal boron nitride/graphene (G/h-BN/G) heterojunction. The internal stress can regulate the band structure of the heterojunction, altering the tunneling barrier height and thereby enhancing the carriers tunneling effect. The theoretical model of tunneling current and applied gas pressure was set up by simulations combining the finite element method, first-principles calculations, and the Fowler-Nordheim (F-N) tunneling method. To realize it, a gas pressure sensor based on the G/h-BN/G heterostructure membrane was designed and fabricated. The experimental results reveal that the sensor has a high sensitivity of 8.31×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> kPa<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> with the sensing membrane area of 78.5 μm². Compared to existing graphene-based pressure sensors, the sensitivity is improved by 10-100 times, while the size of sensitive film reduces by an order of magnitude. This study proposes a novel principle for gas pressure detection, providing a novel perspective on the advancement of highly sensitive, compact pressure sensors, and paving the way for broader applications across multiple sectors..