Structural modifications of gold thin films produced by thiol-derivatized single-stranded DNA immobilization.
Recent experiments have reported an opposite sign of the differential surface stress produced on gold-coated cantilevers by a thiol-derivatized single-stranded DNA (SH-DNA) immobilization process. The sign of the surface stress depends on the method used to evaporate the gold thin film, being compressive (negative) or tensile (positive) for e-beam or resistively deposited gold, respectively. This study investigates the origin of this effect by means of a combination of x-ray diffraction and x-ray photoelectron spectroscopy. Both e-beam and resistively grown gold thin films are characterized to find the subtle differences responsible for this intriguing stress behaviour. Somewhat remarkably, these studies show a tight relation between the surface structure of the gold overlayer and the SH-DNA immobilization efficiency. The average grain size variation seems to correlate well with the differential surface stress triggered by the SH-DNA immobilization previously reported. These results suggest that the relation of the probe molecules with the surface structure must be considered to understand surface stress changes.
IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid, Spain.
María
M
Arroyo-Hernández
Martin
M
Svec
Celia
C
Rogero
Carlos
C
Briones
José Angel
JA
Martín-Gago
José Luis
JL
Costa-Krämer
D004277:DNA, Single-Stranded / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D061925:Immobilized Nucleic Acids / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties
D004277:DNA, Single-Stranded; D061925:Immobilized Nucleic Acids; D013438:Sulfhydryl Compounds; D006046:Gold