Comparison of ZnO and Ti-doped ZnO sensing membrane applied in electrolyte-insulator-semiconductor structure

• Published in: Ceramics international Vol. 44; no. 6; pp. 6081 - 6088
• Main Authors: Lee, Ming Ling, Wang, Jer Chyi, Kao, Chyuan Haur, Chen, Hsiang, Lin, Chan Yu, Chang, Che Wei, Mahanty, Rama Krushna, Lin, Chun Fu, Chang, Kow Ming
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.04.2018
• Subjects: Biosensing; RTA; Ti doped; Urea; ZnO; Ti doped; Urea; ZnO; RTA; Biosensing
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2017.12.239

In this paper, we demonstrate electrolyte-insulator-semiconductor devices for biochemical sensing applications prepared from ZnO and Ti-doped ZnO sensing membranes deposited on Si substrates by radio frequency sputtering. The structural, morphological, and compositional features of these deposited films with multitemperature annealing were studied using X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy, respectively. Sensitivity, linearity, hysteresis, and drift rate were measured to determine the sensing and reliability performance of all fabricated devices. Compared to the ZnO electrolyte-insulator-semiconductor (EIS), the Ti-doped ZnO EIS sensor annealed at 700°C exhibits a higher sensitivity of 57.56mV/pH, lower hysteresis of 2.79mV, and lower drift rate of 0.29mV/h. For Ti-doped ZnO, sensitivities of 3.62mV/mM and 6.42mV/mM were obtained for urea and glucose sensing, respectively. The improvements are owing to Ti-doping, which produces a rougher sensing surface, a well-crystallized grain structure, and thinner silicate and SiO2 at the silicon-oxide interface.