Comparison of Magnesium and Titanium Doping on Material Properties and pH Sensing Performance on SbO Membranes in Electrolyte-Insulator-Semiconductor Structure.

In this research, electrolyte-insulator-semiconductor (EIS) capacitors with SbO sensing membranes were fabricated. The results indicate that Mg doping and Ti-doped SbO membranes with appropriate annealing had improved material quality and sensing performance. Multiple material characterizations and sensing measurements of Mg-doped and Ti doping on SbO sensing membranes were conducted, including of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). These detailed studies indicate that silicate and defects in the membrane could be suppressed by doping and annealing. Moreover, compactness enhancement, crystallization and grainization, which reinforced the surface sites on the membrane and boosted the sensing factor, could be achieved by doping and annealing. Among all of the samples, Mg doped membrane with annealing at 400 °C had the most preferable material properties and sensing behaviors. Mg-doped SbO-based with appropriate annealing are promising for future industrial ionsensing devices and for possible integration with SbO-based semiconductor devices.