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Article

Impact of Surface Chemistry and Doping Concentrations on Biofunctionalization of GaN/Ga‒In‒N Quantum Wells

1
Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
2
Institute of Functional Nanosystems, Ulm University, Albert-Einstein-Allee 45, D-89081 Ulm, Germany
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Institute of Quantum Matter/Semiconductor Physics Group, Ulm University, Albert-Einstein-Allee 45, D-89081 Ulm, Germany
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Department of Chemistry, SRM University AP Andhra Pradesh, Andhra Pradesh 522502, India
5
Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
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Fraunhofer Institute for Applied Solid State Physics, Tullastrasse 72, D-79108 Freiburg, Germany
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Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081 Ulm, Germany
*
Author to whom correspondence should be addressed.
Sensors 2020, 20(15), 4179; https://doi.org/10.3390/s20154179
Received: 24 June 2020 / Revised: 21 July 2020 / Accepted: 23 July 2020 / Published: 28 July 2020
(This article belongs to the Special Issue Thin-Film Materials and Nanostructure Devices Applicable for Sensing)
The development of sensitive biosensors, such as gallium nitride (GaN)-based quantum wells, transistors, etc., often makes it necessary to functionalize GaN surfaces with small molecules or even biomolecules, such as proteins. As a first step in surface functionalization, we have investigated silane adsorption, as well as the formation of very thin silane layers. In the next step, the immobilization of the tetrameric protein streptavidin (as well as the attachment of chemically modified iron transport protein ferritin (ferritin-biotin-rhodamine complex)) was realized on these films. The degree of functionalization of the GaN surfaces was determined by fluorescence measurements with fluorescent-labeled proteins; silane film thickness and surface roughness were estimated, and also other surface sensitive techniques were applied. The formation of a monolayer consisting of adsorbed organosilanes was accomplished on Mg-doped GaN surfaces, and also functionalization with proteins was achieved. We found that very high Mg doping reduced the amount of surface functionalized proteins. Most likely, this finding was a consequence of the lower concentration of ionizable Mg atoms in highly Mg-doped layers as a consequence of self-compensation effects. In summary, we could demonstrate the necessity of Mg doping for achieving reasonable bio-functionalization of GaN surfaces. View Full-Text
Keywords: n-type GaN; p-type GaN; biosensor; chemical functionalization; protein adsorption; self-assembled monolayer n-type GaN; p-type GaN; biosensor; chemical functionalization; protein adsorption; self-assembled monolayer
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MDPI and ACS Style

Naskar, N.; Schneidereit, M.F.; Huber, F.; Chakrabortty, S.; Veith, L.; Mezger, M.; Kirste, L.; Fuchs, T.; Diemant, T.; Weil, T.; Behm, R.J.; Thonke, K.; Scholz, F. Impact of Surface Chemistry and Doping Concentrations on Biofunctionalization of GaN/Ga‒In‒N Quantum Wells. Sensors 2020, 20, 4179. https://doi.org/10.3390/s20154179

AMA Style

Naskar N, Schneidereit MF, Huber F, Chakrabortty S, Veith L, Mezger M, Kirste L, Fuchs T, Diemant T, Weil T, Behm RJ, Thonke K, Scholz F. Impact of Surface Chemistry and Doping Concentrations on Biofunctionalization of GaN/Ga‒In‒N Quantum Wells. Sensors. 2020; 20(15):4179. https://doi.org/10.3390/s20154179

Chicago/Turabian Style

Naskar, Nilanjon, Martin F. Schneidereit, Florian Huber, Sabyasachi Chakrabortty, Lothar Veith, Markus Mezger, Lutz Kirste, Theo Fuchs, Thomas Diemant, Tanja Weil, R. J. Behm, Klaus Thonke, and Ferdinand Scholz. 2020. "Impact of Surface Chemistry and Doping Concentrations on Biofunctionalization of GaN/Ga‒In‒N Quantum Wells" Sensors 20, no. 15: 4179. https://doi.org/10.3390/s20154179

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