Charge transfer-induced enhancement of a Raman signal in a hybrid Ag-GaN nanostructure.

A hybrid system consisting of Ag nanoparticles dispersed onto a GaN nanowall network (GaN NWN) exhibited characteristic optical properties and electronic band structure. Surface-sensitive XPS studies of this high-surface-area system revealed the presence of a high surface charge carrier concentration due to dangling bonds, which resulted in a high metal-like surface conductivity. The low coverage of absorbed Ag led to the nanocluster formation, facilitating charge transfer from GaN to Ag, and thereby further increasing the surface charge carriers.

Nano-morphology induced additional surface plasmon resonance enhancement of SERS sensitivity in Ag/GaN nanowall network.

The GaN nanowall network, formed by opening the screw dislocations by kinetically controlled MBE growth, possesses a large surface and high conductivity. Sharp apexed nanowalls show higher surface electron concentration in the band-tail states, in comparison to blunt apexed nanowalls. Uncapped silver nanoparticles are vapor deposited on the blunt and sharp GaN nanowall networks to study the morphological dependence of band-edge plasmon-coupling.