Lithographically Patterned Thin Activated Carbon Films as a New Technology Platform for On-Chip Devices

Abstract

Continuous, smooth, visibly defect-free, lithographically patterned activated carbon films (ACFs) are prepared on the surface of silicon wafers. Depending on the synthesis conditions, porous ACFs can either remain attached to the initial substrate or be separated and transferred to another dense or porous substrate of interest. Tuning the activation conditions allows one to change the surface area and porosity of the produced carbon films. Here we utilize the developed thin ACF technology to produce prototypes of functional electrical double-layer capacitor devices. The synthesized thin carbon film electrodes demonstrated very high capacitance in excess of 510 F g^–1 (>390 F cm^–3) at a slow cyclic voltammetry scan rate of 1 mV s^–1 and in excess of 325 F g^–1 (>250 F cm^–3) in charge–discharge tests at an ultrahigh current density of 45 000 mA g^–1. Good stability was demonstrated after 10 000 galvanostatic charge–discharge cycles. The high values of the specific and volumetric capacitances of the selected ACF electrodes as well as the capacity retention at high current densities demonstrated great potential of the proposed technology for the fabrication of various on-chip devices, such as micro-electrochemical capacitors.