The sensitivity to relative humidity (RH) variations in the range 0%-90% of a platinum polyyne, namely poly-[1,4-dihexadecyloxy-2,5-diethynylbenzene-bis(triphenylphosphine) platinum(II)] (Pt-P-HDOB) membrane was investigated by means of a surface acoustic wave (SAW) based sensor. A thin film of polymeric membrane was spin deposited on the free surface of the device and the resulting acoustic velocity and attenuation perturbations allowed the acoustic characterization of the membrane by means of the perturbation theory. The SAW sensor was able to reveal even very low (<10% RH) humidity conditions at room temperature, with high reproducibility, repeatability and stability. (C) 2002 American Institute of Physics

Effect of humidity on hydrogen sensitivity of Pt-gated AlGaN/GaN high electron mobility transistor based sensors Appl. Phys. Lett. 96, 232106 (2010); 10.1063/1.3454279 Epitaxial growth and orientation of AlN thin films on Si(001) substrates deposited by reactive magnetron sputtering

This paper deals with some advances in surface acoustic wave (SAW) sensor research relating to the use of both a new chemically interactive material (metal porphyrin) and new amplifiers for low-noise SAW oscillators, which are illustrated and discussed in some detail. The trend toward SAW matrixes, implemented on silicon, required for more sensitive chemical image systems, has led to the observation of coupling effects between adjacent SAW oscillators, even if the electronics were not implemented on Si. This effect must be considered at design level in order to achieve a higher resolution value in detecting either single chemical species or chemical images.

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Highly c-axis oriented piezoelectric AlN films were sputtered on (0001) Al2O3 substrates and four gigahertz-range surface acoustic wave (SAW) electroacoustic coupling configurations were realized by conventional photolithographic process. The thermal sensitivity of each device was experimentally estimated and found in good accordance with the theoretical predictions. Eight gigahertz-range, thermally compensated SAW devices were obtained for specific AlN thickness, SAW propagation direction, and electrical boundary conditions. A theoretical analysis of the acoustic and electrical behavior of the four coupling structures is proposed to match the achievable performances of the SAW devices with the design requirements.