Photochemical functionalization of gallium nitride thin films with molecular and biomolecular layers.
We demonstrate that photochemical functionalization can be used to functionalize and photopattern the surface of gallium nitride crystalline thin films with well-defined molecular and biomolecular layers. GaN(0001) surfaces exposed to a hydrogen plasma will react with organic molecules bearing an alkene (C=C) group when illuminated with 254 nm light. Using a bifunctional molecule with an alkene group at one end and a protected amine group at the other, this process can be used to link the alkene group to the surface, leaving the protected amine exposed. Using a simple contact mask, we demonstrate the ability to directly pattern the spatial distribution of these protected amine groups on the surface with a lateral resolution of <12 mum. After deprotection of the amines, single-stranded DNA oligonucleotides were linked to the surface using a bifunctional cross-linker. Measurements using fluorescently labeled complementary and noncomplementary sequences show that the DNA-modified GaN surfaces exhibit excellent selectivity, while repeated cycles of hybridization and denaturation in urea show good stability. These results demonstrate that photochemical functionalization can be used as an attractive starting point for interfacing molecular and biomolecular systems with GaN and other compound semiconductors.
Kim
Heesuk
H
Department of Chemistry, University of Wisconsin-Madison, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Colavita
Paula E
PE
Metz
Kevin M
KM
Nichols
Beth M
BM
Sun
Bin
B
Uhlrich
John
J
Wang
Xiaoyu
X
Kuech
Thomas F
TF
Hamers
Robert J
RJ
D000081:Acetamides; D000473:Alkanes / Q000737:chemistry; D000475:Alkenes / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry*; D005463:Fluoroacetates; D005708:Gallium / Q000737:chemistry*; D008567:Membranes, Artificial; D008956:Models, Chemical; D015394:Molecular Structure; D010777:Photochemistry; D013057:Spectrum Analysis; D013499:Surface Properties; D014269:Trifluoroacetic Acid / Q000737:chemistry
C413406:10-aminodec-1-ene; D000081:Acetamides; D000473:Alkanes; D000475:Alkenes; D003432:Cross-Linking Reagents; D004277:DNA, Single-Stranded; D005463:Fluoroacetates; D008567:Membranes, Artificial; C473348:gallium nitride; C030688:trifluoroacetamide; D005708:Gallium; D014269:Trifluoroacetic Acid