DNA molecular ruler-modulated photoluminescence enhancement of gallium arsenide modified with plasmonic nanoparticles

The interaction between plasmonic metal nanocrystals and semiconducting materials gives rise to very interesting phenomena, including fluorescence enhancement and fluorescence quenching, resulting in various bioanalytical applications. Here we report the utilizing of a DNA molecular ruler to modulate the plasmonic enhancement of gallium arsenide (GaAs) photoluminescence with gold nanoparticles. A well-defined nanostructure was first developed based on controlled assembly of the gold nanopaticles on the GaAs surface using DNA scalfold as a bridge at tunable intramolecular distance. Then, we demonstrated the DNA length-dependent fluorescence enhancement of GaAs with gold nanoparticles is mainly attributed to the surface plasmon coupling effect. This finding suggests the great promise of the DNA-modulated coupled plasmonics in the development of more efficient optical sensing and devices.