Scanning and measurement of carbon nanofiber nanoelectrode arrays using Atomic Force Microscopy

One of the major limitations in the development of ultrasensitive electrochemical biosensors based on one-dimensional nanostructure is the difficulty involved with reliably fabricating nanoelectrode arrays (NEAs). In previous work, a simple, robust and scalable wafer-scale fabrication method to produce multiplexed biosensors is introduced. Each sensor chip consists of nine individually addressable arrays that uses electron beam patterned vertically aligned carbon nanofibers (VACNFs) as the sensing element. To ensure nanoelectrode behavior with higher sensitivity, VACNFs were precisely grown on 100 nm Ni dots with 1 ¿m spacing on each micro pad. However, in order to examine the quality and measure the height and diameter of the VACNFs, some surface detection and measurement tool at the nanoscale level is needed. In this paper, we introduce an approach to measure these nano-scale features through atomic force microscope (AFM). With this method, both the 2D and 3D images of sample surface are generated and the sizes of carbon nanofibers and cavities are obtained. Furthermore, statistical analysis is carried out to enable improvement of VACNFs growth and fabrication.