(Invited) Effects of Environmental Exposure on Stability and Conductance Poly-l-lysine Coated AlGaN/GaN High Electron Mobility Transistors
Here, GaN based biosensors were fabricated, functionalized, and then tested with simulated solutions in which the HEMT biosensors would be expected to function. AlGaN/GaN HEMTs were grown via MOCVD (Fig. 1) and functionalized via physisorption of recognition peptides. HEMTs were tested in physiologically relevant solutions as well as controlled solution. Analysis was done upon initial peptide binding via AFM, XPS, and IV measurements. This was repeated after environmental exposure was completed over variable periods of time. The results show the stability of the surface over extended cycles along with the benefits associated with the functionalization of the device. The detailed surface and electrical characterization is essential for quality control and integrity of future sensor development based on GaN devices.
 M.S. Makowski, and A. Ivanisevic, “Molecular analysis of blood with micro/nanoscale field-effect-transistor biosensors,” Small, 7(14)1863 (2011)
 S. Jewett, M.S. Makowski, B. Andrews, M. Manfra, A. Ivanisevic, “Gallium nitride is biocompatible and non-toxic before and after functionalization with peptides,” Acta Biomaterialia, 8(2)728 (2012)
 A. Ramesh, F. Ren and P. Berger, “Towards in vivo biosensors for low-cost protein sensing,” Electronics Letters, 49(7) 450 (2013)
 M.S. Makowski, I. Bryan, R. Collazo, Z. Sitar, A. Ivanisevic, J. Xie, and C. Arellano, “Kinase detection with gallium nitride based high electron mobility transistors,” Applied Physics Letters, 103(8) (2013)