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Optimization of Urea-EnFET Based on Ta2O5 Layer with Post Annealing
Department of Electronic Engineering, Chang Gung University, 259 Wen-Hwa 1 st road,Kwei-Shan, Tao-Yuan, 333, Taiwan
Device Section, Department of WAT and Devices, Inotera Memories Inc., 667 Fuhsing 3rd Road, Hwa-Ya Technology Park, Kwei-Shan, Tao-Yuan, 333, Taiwan
Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ul. Ks. Trojdena 4, 02-109 Warsaw, Poland
Biosensor Group, Biomedical Engineering Research Center, Chang Gung University, 259 Wen-Hwa 1 st road, Kwei-Shan, Tao-Yuan, 333, Taiwan
* Author to whom correspondence should be addressed.
Received: 4 March 2011; in revised form: 30 March 2011 / Accepted: 11 April 2011 / Published: 27 April 2011
Abstract: In this study, the urea-enzymatic field effect transistors (EnFETs) were investigated based on pH-ion sensitive field effect transistors (ISFETs) with tantalum pentoxide (Ta2O5) sensing membranes. In addition, a post N2 annealing was used to improve the sensing properties. At first, the pH sensitivity, hysteresis, drift, and light induced drift of the ISFETs were evaluated. After the covalent bonding process and urease immobilization, the urea sensitivity of the EnFETs were also investigated and compared with the conventional Si3N4 sensing layer. The ISFETs and EnFETs with annealed Ta2O5 sensing membranes showed the best responses, including the highest pH sensitivity (56.9 mV/pH, from pH 2 to pH 12) and also corresponded to the highest urea sensitivity (61 mV/pCurea, from 1 mM to 7.5 mM). Besides, the non-ideal factors of pH hysteresis, time drift, and light induced drift of the annealed samples were also lower than the controlled Ta2O5 and Si3N4 sensing membranes.
Keywords: urea; enzymatic field effect transistor (EnFET); ion sensitive field effect transistor (ISFET); tantalum pentoxide (Ta2O5); post N2 annealing
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MDPI and ACS Style
Lue, C.-E.; Yu, T.-C.; Yang, C.-M.; Pijanowska, D.G.; Lai, C.-S. Optimization of Urea-EnFET Based on Ta2O5 Layer with Post Annealing. Sensors 2011, 11, 4562-4571.
Lue C-E, Yu T-C, Yang C-M, Pijanowska DG, Lai C-S. Optimization of Urea-EnFET Based on Ta2O5 Layer with Post Annealing. Sensors. 2011; 11(5):4562-4571.
Lue, Cheng-En; Yu, Ting-Chun; Yang, Chia-Ming; Pijanowska, Dorota G.; Lai, Chao-Sung. 2011. "Optimization of Urea-EnFET Based on Ta2O5 Layer with Post Annealing." Sensors 11, no. 5: 4562-4571.