Design and Optimization of Suspended 1D Nanoheaters for Low Power Gas Sensors

Abstract

Gas sensors play a critical role in a wide range of applications, including smart healthcare, environmental monitoring, and industrial process control. In particularly, Internet of Things(IoT) applications demand sensor platforms that are highly miniaturized, low cost, and low power consumption. Among various gas sensing technologies, thermal conductivity detector (TCD)–type and metal oxide semiconductor (MOS) gas sensors are attractive due to their compatibility with MEMS- based fabrication and cost-effective mass production. However, both sensor types rely on integrated heaters to supply thermal energy, resulting in increased power consumption and limiting their applicability in low-power environments. In this work, a Carbon-MEMS–based suspended one-dimensional (1D) nanoheater platform is proposed to address these limitations. The platform utilizes the volumetric shrinkage of polymer structures during pyrolysis to fabricate suspended carbon backbones at the wafer scale through a simple and batch-compatible process. By tuning the electrical conductivity of carbon with pyrolysis temperature, electrically insulating carbon backbones were employed as structural supports. A metal heater wider than the carbon nanowire was selectively deposited to form a suspended nanoheater, while a transverse cut-off wire functioned as a built-in shadow mask, eliminating the need for additional substrate etching steps. This design significantly simplifies fabrication while preserving electrical isolation of the suspended region. The thermal behavior of the proposed suspended 1D nanoheater was systematically investigated through numerical simulations, and key geometric parameters were optimized to enhance thermal performance. The optimized structure exhibits an ultrafast thermal response with a sub-microsecond thermal time constant (~0.6 μs) and ultra-low power consumption, making it well suited for TCD-type gas sensing and other thermal-based sensing applications. In addition, the platform was extended to MOS-type gas sensors by introducing a suspended grid- shaped carbon backbone capable of supporting various sensing materials. A serpentine-shaped 1D nanoheater was integrated onto the grid structure. Simulation-based optimization demonstrated improved compatibility with duty-cycled operation, enabling significant reduction in average power consumption. Owing to its suspended configuration, low thermal mass, and versatile material integration capability, the proposed grid-type platform enables low-power MOS gas sensing and offers potential for integration into systems such as gas chromatography.