Tailoring Responsivity and Speed in Ga ₂ O ₃ -Resonant Nanoelectromechanical Systems Sensors via Thermal Pathway Engineering

Resonant photothermal sensors offer a powerful alternative to conventional photoelectric detectors by bypassing carrier-dynamic limitations; however, they are traditionally constrained by a fundamental trade-off between responsivity and response speed. Here, we demonstrate a design strategy to balance it via thermal pathway engineering. By treating thermal conductance as a primary design parameter, we show that sensor performance can be tailored to meet specific application demands. We validate this framework using doubly clamped β-Ga2O3 nanoelectromechanical systems (NEMS) resonators as a model system, utilizing multiphysics simulations to optimize thermal-mechanical transduction. Our results reveal that by manipulating resonator geometry and introducing electrode thermal shunts, the resonant frequency modulation can be precisely controlled. We report a frequency responsivity of –175.5 Hz/nW and a noise equivalent power NEPth = 2.5 × 10−13 W/Hz1/2. Crucially, we demonstrate that the response time can be accelerated from milliseconds to microseconds through engineered thermal shunting. This work provides a generalized toolkit for customizable resonant optical sensing.