Download Functionalization of Gallium Nitride with Octadecyltrichlorosilane

Functionalization of Gallium Nitride with Octadecyltrichlorosilane Self –Assembled
Monolayers
Christina Arisio and Marya Lieberman
University of Notre Dame
Gallium nitride is a transparent wide-bandgap semiconductor of interest for biosensor
applications. Surface functionalization is often useful in such applications to provide an
attachment anchor for the sensor’s target species. Gallium nitride, with a thin passivating
layer of Ga2O3, was successfully functionalized with an octadecyltrichlorosilane (OTS)
self-assembled monolayer (SAM). Water contact angles, atomic force microscopy, and
x-ray photoelectron spectroscopy were used for characterization of the bare and
functionalized surfaces. SAM stability was tested in air and in various solvents. OTS
SAM’s on GaN were stable in acetonitrile, but unstable in aqueous solvents. The OTS
SAM’s desorb after several hours to days in common buffer solutions, which is a concern
for biological applications of derivatized GaN surfaces. Shown: AFM images of timed
OTS monolayer growth on the surface of GaN.