AVS 53rd International Symposium
    Surface Science Monday Sessions
       Session SS2-MoA

Paper SS2-MoA6
Photochemical Functionalization and Chemical Patterning of Gallium Nitride Thin Films with Biomolecular Layers

Monday, November 13, 2006, 3:40 pm, Room 2004

Session: Functionalization of Semiconductor Surfaces
Presenter: H. Kim, University of Wisconsin at Madison
Authors: H. Kim, University of Wisconsin at Madison
P. Colavita, University of Wisconsin at Madison
K. Metz, University of Wisconsin at Madison
B.M. Nichols, University of Wisconsin at Madison
B. Sun, University of Wisconsin at Madison
J.J. Uhlrich, University of Wisconsin at Madison
X. Wang, University of Wisconsin at Madison
T.F. Kuech, University of Wisconsin at Madison
R.J. Hamers, University of Wisconsin at Madison
Correspondent: Click to Email
Gallium nitride is a particularly intriguing semiconductor for sensing applications because it can be grown as a thin crystalline film and because the high ionic character of GaN causes the intrinsic surface states to be near the respective band edges, where they have less impact on the interfacial electronic properties. We have investigated the functionalization of gallium nitride (0001) surfaces with well-defined molecular and biomolecular layers. After cleaning in a hydrogen plasma, GaN surfaces were reacted photochemically with organic alkenes bearing protected amine groups using ultraviolet light. Using a simple contact mask to control the UV light, we demonstrate the ability to directly pattern chemical groups onto the surface with a spatial resolution of <12 microns. After linking to the surface, the molecules groups were deprotected and used to link DNA oligonucleotides to the GaN surface. Measurements using fluorescently labeled complementary and non-complementary sequences showed that the DNA-modified GaN surfaces exhibit excellent selectivity, and repeated cycles of hybridization and denaturation show good stability. These results demonstrate that GaN can be used as an alternative substrate for molecular and biological sensing applications.