Julia Fritsch

Nanoimprint patterning of thin cadmium stannate films using a polymeric precursor route

The synthesis of cadmium stannate (Cd2SnO4 CTO) nanoparticle powders and the deposition and patterning of thin Cd2SnO4 films were achieved via a polymeric precursor approach. Conditions for the phase formation of the cubic spinel phase were evaluated, and for the first time the system was obtained in single phase powder form from a precursor system. Thin Cd2SnO4 films were prepared by spin coating the polymeric precursor solution followed by thermal treatment. Highly transparent and 20 nm thick films with a minimum sheet resistance of 110 Ohm were prepared. A thermal imprint process with PDMS molds was used for patterning of the films in the sub-micrometre range. Nanostructured CTO films are essential to improve structured electrodes in opto-electronic devices such as CdTe-based thin film solar cells.

Semi-transparent silver electrodes for flexible electronic devices prepared by nanoimprint lithography

The preparation of mechanically flexible and optically transparent electronic circuits plays a key role in the development of next-generation display technologies. Silver nano-gratings are of particular interest due to their excellent conductivity and adjustable transmittance. Printed on polymeric substrates they are suitable for an application in flexible opto-electronic devices. Here, we present the preparation of a smart silver precursor system combining both the ability of cheap and scalable nanoimprint patterning and simple thermal silver reduction. Homogeneous silver line and grid patterns with line widths down to 400 nm are prepared using poly(dimethylsiloxane) stamps in a thermal nanoimprint lithography process. Relatively low process temperatures allow the film formation on polymeric substrates. Semi-transparent silver electrodes with a resistance of 2.8 ohm are patterned on polyimide foils to prepare flexible electro-luminescence devices. A detailed investigation of the precursors thermal decomposition behaviour as well as the resulting electrical and optical properties of the films is offered.