Inorganic Naostructures on surfaces Using Micellar Diblock Copolymer Templates

摘要

We present a genral method for generating rather regualr arrays of nanometer sized noble metal and metal oxide clusters on flat substrates by the use of a polymer template. In a first step micelles from polystrene-bloc-poly(2-vinylpyridine) and polystyrene-block-poly (ethylene oxide) in toluene are used as nanocomprtments which are loaded by a defined amount of HAuCl_4 or LiAuCl_4. In a subsequent step the Au(III) ions can be reduced i nsuch a way that exactly one gold particle is formed in each micelle. When a flat substrate is dipped into a dilute solution of the Au or Au(III) loaded micelles, a monomicellar film is deposited in which the gold is arranged in a mesoscopic near to hexagonal 2-D lattice. Treatment by an oxygen plasma allows the removal of the polymer completely, and irrespective of whether the gold was reduced first, naked clusters of the elementary metal are deposited on the substrate with uniform sizes between 1 and 15nm and within tunable distances of 10-200nm. In a further step such regular micellar films are used as masks for nanolithography by argon sputtering. This way the micellar pattern can be used to generate a surface relief in an underlying layered semiconducting substrate. The inorganic / organic block copolymer film can be tailored from a negative to a positive resist.