EBL/NIL fabrication and characterization of interdigitated electrodes for potential application in combinatorial studies
- PDF / 3,236,504 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 78 Downloads / 171 Views
1024-A02-04
EBL/NIL fabrication and characterization of interdigitated electrodes for potential application in combinatorial studies. Lars Henrik Dæhli Skjolding1,2, Christer Spégel3, Jenny Emnéus2, and Lars Montelius1 1 Division of Solid State Physics, Lund University, Box 118, Lund, SE-22100, Sweden 2 Department of Micro and Nanotechnology, Technical University of Denmark, Kgs. Lyngby, DK-2800, Denmark 3 Department of Analytical Chemistry, Lund University, Box 124, Lund, SE-221 00, Sweden ABSTRACT Electrochemical transducers are frequently used to electrochemically deposit, synthesize and/or sense chemical compounds in material science, chemistry and biology. Traditionally this is done in fairly large volumes; generally several milliliters to even full production scale tanks, however, for high-throughput measurements and combinatorial experiments smaller volumes are generally preferred. To probe small volumes small electrodes with preferable high density are needed. Presented in this paper is how to fabricate interdigitated electrodes by electron beam lithography (EBL) and also how to make large quantities by nanoimprint lithography (NIL) to enable combinatorial studies of cells or materials in microsystems (Lab-on-a-Chip Systems). Interdigitated electrodes are shown to have additional advantages compared to simple disk or rod electrodes, such as being able to perform redox cycling experiments. The collection efficiency for the electrodes with pitch of 400 nm and width of 200 nm fabricated by EBL has been found to be round 87% when characterized electrochemically using ferro-/ferricyanide. The shape of the cyclic voltammograms for the electrodes are also in good agreement with the theoretical expectations for ultramicroelectrodes. Hence, these electrodes should be ideal candidates for high-throughput and combinatoraial studies based on electrochemical methods. Furthermore, a fabrication process based on nanoimprint lithography (NIL) is demonstrated, this could potentially ease fabrication and reduce cost of devices. The NIL process is based on thermal imprinting in PMMA 950k and LOR 0.7A. INTRODUCTION Electrochemical methods are commonly applied across the scientific disciplines to either synthesize or characterize processes or materials. Some studies combine both synthesis and characterization to enable high-throughput investigations, as documented by Kulikov and Mirsky [1], who have used interdigitated electrodes to synthesize and study conductive polymers. Electrochemical methods are generally easily scalable, however, diffusion phenomena play a strong role in any electrochemical process, hence the dynamics of the system are size and geometry dependent. By miniaturizing the electrodes other phenomena can be investigated like fast dynamics for ultramicroelectrodes and unstable intermediates for small interdigitated electrodes. Ultramicroelectrodes has been used for electrochemical studies since the early 1980’s [4, 5]. One of the main characteristics of ultramicroelectrodes is that diffusion is predominantly ra
Data Loading...
