Low equivalent series resistance (ESR) silicon-based on-chip supercapacitors

In this paper, we report the fabrication and optimization of current collectors on the supercapacitors based on a black silicon substrate with highly-dense carbon nanotube layers grown by atmospheric pressure chemical vapor deposition (APCVD) method for low equivalent series resistance (ESR). The as-grown CNTs displayed an excellent capacitive behavior with the corresponding specific capacitance of 126.7 mF/cm² in the organic electrolyte at the scan rate of 10 mV/s. In order to reduce the ESR, we presented a feasible fabrication method to form a top Au current collector on the CNTs layer by DC sputtering technology. After coated with the Au layer, the ESR of the coin-cell type supercapacitor is reduced by 31% from 0.19 Ω/cm² to 0.13 Ω/cm². These results show that the top Au current collector could improve the performances for on-chip supercapacitors. We also expect this method could bring a potential breakthrough in the mass production of on-chip supercapacitors.