Impedance Characterization of DNA-functionalization Layers on AlGaN/GaN High Electron Mobility Transistors. (2015)

• Record Type: Journal Article
• Authors: Espinosa, N.; Schwarz, S.U.; Cimalla, V.; Podolska, A.; Ambacher, O.
• Is Part Of: Procedia engineering. Volume 120(2015)
• Page Start: 912
• Page End: 915
• Publication Date: 2015
• Subjects: GaN/AlGaN HEMT -- DNA layer characterization -- charge transfer resistance -- Warburg element -- dynamic detection; Engineering -- Congresses; Engineering -- Periodicals; Engineering; Conference proceedings; Periodicals; 620.005
• DOI: 10.1016/j.proeng.2015.08.790
• Languages: English
• ISSNs: 1877-7058

Abstract

Abstract: Characterization and optimization for biosensor implementation with open gate AlGaN/GaN transistors is described. Probe-DNA was immobilized on the gate. As target, complementary DNA at 10 -12 - 10 -7 mol/L was added. To investigate the impedimetric properties of the sensing area, electrochemical impedance spectroscopy was used. For very low frequencies, the bio-functionalization layer was modeled as a membrane with a charge transfer resistor in series with a Warburg element. This component presents impedance to diffusion of electrolyte ions. Its behavior is intermediate between a capacitor and a resistor (membrane impedance). After probe-target matching, the charge transfer resistance and Warburg impedance were increased (lower flow of electrolyte ions through the membrane). Using this working principle, a dynamic detection of targets is proposed.