A Study of Surface-Etched Microgroove Depth on the Performance of QTFs

We report a comprehensive theoretical and simulation-based examination of how the depth of microgrooves etched onto the prongs of quartz tuning fork (QTF) influences key physical parameters, namely the quality factor (Q), resonance frequency (f), and surface charge density, which are critical to the operational efficacy of QTFs. Two distinct types of microgrooves were fabricated for quartz tuning forks operating at a frequency of 9 kHz, with three varying depths of 20 μm, 44 μm, and 88 μm, respectively. Subsequent quartz-enhanced photoacoustic spectroscopy (QEPAS) gas measurement experiments were conducted utilizing these QTFs. The findings indicate a general trend wherein an increase in microgroove depth results in a slight elevation in resonance frequency, a significant reduction in quality factor, and a peak in gas sensing signal that initially rises and then falls. The study explores the underlying mechanisms of these observations and posits that an optimal balance must be achieved regarding microgroove depth in the design of practical tuning fork structures. Finally, the paper outlines potential avenues for future research regarding the etching depth of the surface-etched microgrooves in QTFs.