High dielectric constant PrYxOy sensing films electrolyte-insulator-semiconductor pH-sensor for the detection of urea

In this paper, we describe the structural and sensing properties of high-k PrYxOy sensing films deposited on Si substrates through reactive co-sputtering. Secondary ion mass spectrometry and atomic force microscopy were employed to analyze the compositional and morphological features of these films after annealing at various temperatures. The electrolyte-insulator-semiconductor (EIS) device incorporating a PrYxOy sensing membrane that had been annealed at 800 degrees C exhibited good sensing characteristics, including a high sensitivity (59.07 mV pH(-1) in solutions from pH 2 to 12), a low hysteresis voltage (2.4 mV in the pH loop 7 -> 4 -> 7 -> 10 -> 7), and a small drift rate (0.62 mV h(-1) in the buffer solution at pH 7). The PrYxOy EIS device also showed a high selective response towards H+. This improvement can be attributed to the small number of crystal defects and the large surface roughness. In addition, the enzymatic EIS-based urea biosensor incorporating a high-k PrYxOy sensing film annealed at 800 degrees C allowed the potentiometric analysis of urea. at concentrations ranging from 1 to 16mM, with a sensitivity of 9.59 mV mM(-1). (C) 2009 Elsevier B.V. All rights reserved.