A Fast-Startup Self-Sustained Thermal-Piezoresistive Oscillaror with >10⁶ Effective Quality Factor In The Air

This paper reports a self-sustained thermal-actuation piezoresistive-detection oscillator with boosted startup time and quality (Q) factor in the order of a million. A high Q-factor is an essential property for resonant sensors to achieve a high signal to noise ratio. It is demonstrated that the thermal-piezoresistive effect can increase the Q-factor. We obtained an effective Q-factor up to 1.06 million operating in air with direct-current induced self-oscillation. Furthermore, a fast startup time is achieved when stimulating the self-sustained oscillator with a current just below the threshold of self-oscillation requirements. The experimental results show that the startup time can be decreased by a factor of ~3 by initially thermally pre-expanding the actuating nanobeam compared to a cold-startup condition.