Charge Sensitivity Control of Potentiometric Nanobiosensors

• Applicant: Professorin Dr. Margit Zacharias
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Microsystems
• Term: from 2021 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 461003068

• Final Report Year: 2024

Final Report Abstract

In the project, the implementation of a differential sensor design consisting of sensor and reference field-effect transistor (FET) implemented on a single SnO 2 nanowire (NW) was planned. The reference and the sensor element should differ by their surface parameter α. In addition, the sensing oxide insulator surface was planned to be modified with defined charged molecules for potentiometric biomolecular detection. This includes the preparation of surfaces with negligible surface charge and small pH-sensitivity at operating conditions. The project has been completed with 3 publications, 4 conference papers, and 2 very successful PhD theses. Highlights of the results include: Homogeneous coating of the SnO2 NWs with ALD-synthesized Al2O3. - Precise control of NW growth modes, freestanding and laterally aligned, for application-specific properties. - Crystallographic investigation of the defect distribution in laterally aligned SnO2 NWs. - Epitaxial growth of ALD-ZnO on GaN NWs. - Implementation of multi-contacted SnO2 NWs. - Sensory measurements of SnO2 and ZnO NWs in gas sensors. The experiments could not be conducted as planned, and were performed as possible without missing equipment. As the quality of the ALD coating of the NWs have huge impact on sensor stability and performance, we hence focused especially on the microscopic quality analysis of the NWs and the ALD coating. Normally, ALD coatings are amorphous or polycrystalline, which have disadvantages regarding transport and optical properties. In the framework of the project, for the first time, we were able to demonstrate epitaxial grown NW ALD coating at 300 °C, which represents an important progress.

Publications

• Epitaxial ZnO thin films and NWs, DPG conference Regensburg 2022, Wednesday Session HL 18.6, talk
  M. Kolhep, M. Zacharias & J. Bläsing
  
• Laterally aligned nanowires: Targeted process design and alignment control, DPG conference Regensburg 2022, Thursday Session MM 35.10, talk
  J.-C. Bürger, S. Gutsch & M. Zacharias
  
• Strain and defect location in the crosssection of laterally aligned SnO2 NWs, DPG conference Regensburg 2022, Thursday Session KFM 25.2, poster
  J.-C. Bürger, S. Gutsch & M. Zacharias
  
• Substrate Role in the 0D Nanoparticle-Catalyzed Synthesis of 1D Epitaxial SnO2 Nanostructures, 2022 MRS Fall Meeting, Nov 29,2022, NM07.04.08, talk
  J.-C. Bürger, S. Gutsch, V. Wollersen, D. Wang, C. Kübel & M. Zacharias
  
• Atomic Layer Deposition and Strain Analysis of Epitaxial GaN-ZnO Core–Shell Nanowires. Nano Letters, 23(15), 6920-6926.
  Kolhep, Maximilian; Pantle, Florian; Karlinger, Monika; Wang, Di; Scherer, Torsten; Kübel, Christian; Stutzmann, Martin & Zacharias, Margit
  
• Defect Location in Laterally Aligned Tin Oxide Nanowires: The Role of Growth Direction, Interface Dimensionality, and Catalyst. The Journal of Physical Chemistry C, 127(22), 10871-10877.
  Bürger, Jasmin-Clara; Gutsch, Sebastian; Wollersen, Vanessa; Wang, Di; Christian, Björn; Fu, Zhe; Ambacher, Oliver; Kübel, Christian & Zacharias, Margit
  
• Spontaneous and Position-Controlled Epitaxial Growth of ZnO Nanowires on AlN/Si by CVD. Crystal Growth & Design, 23(10), 7095-7102.
  Kolhep, Maximilian; Bläsing, Jürgen; Strittmatter, André & Zacharias, Margit