Positional control over nanoparticle deposition into nanoholes

Controlled deposition of metal nanoparticles (NPs) into lithographic patterned nanoholes has been a major challenge. Electrostatic attraction was employed in directing gold NPs of precise size into e-beam lithographically patterned holes. Citrate stabilized gold NPs with a net negative surface charge were deposited on a positively charged well-bottom surface generated by adsorption of long-chain amino-terminated organosilane N-(2-aminoethyl)-11-aminoundecyltrimethoxy- silane (AATMS). Scanning electron microscopy (SEM) results indicate that deposition of NPs into patterned holes is a function of deposition time and NPs concentration. Other factors affecting NP fill fraction are thickness of silane and resist layer and spacing between the nanoholes.