Method for fabricating nanoscale patterns on a surface

• Main Authors: Chi, Quijin, Zhang, Jingdong, Andersen, Jens Enevold Thaulov, Ulstrup, Jens, Friis, Esben Peter
• Format: Patent
• Language: English
• Published: 04.06.2002

The present invention relates to a novel process for fabricating nanopits and nanoscale patterns on surfaces of solids at room temperature in a liquid environment by applying extremely small bias voltages in an electrochemical scanning tunnelling microscopy mode. Size-controlled, location selective, and time stable nanopits may be created routinely by this method in a liquid solution without additional experimental set-up. The feasibility of formation and the stability of nanoscale pits and patterns make them of interest for potential applications in the context of information storage, as immobilisation sites for active biological molecules, and in other ways. A novel method to fabricate nanoscale pits on Au(111) surfaces in contact with aqueous solution is claimed. The method uses in situ electrochemical scanning tunnelling microscopy with independent electrochemical substrate and tip potential control and very small bias voltages. This is significantly different from other documented methods, which mostly apply high and short voltage pulses. The most important advantages of the present method are that the dimensions and positions of the pits can be controlled with high precision in aqueous environment so that nanopatterns of the pits can be designed, and that the operations are simple and require no instrumental accessories. Parameters, which control the pit formation and size, have been systematically characterized and show that the primary controlling parameter is the bias voltage. A mechanism based on local surface reconstruction induced by electronic contact between tip and substrate is in keeping with the overall patterns for pit formation. A range of potential applications is proposed.