High K nanophase zinc oxide on biomimetic silicon nanotip array as super-capacitors
H.C. Han, C.W. Chong, S.B. Wang, D. Heh, C.A. Tseng,Y.F. Huang, S. Chattopadhyay, K.H. Chen, C.F. Lin, J.H. Lee, and L.C. Chen,
Nano Letters 13, 1422-1428 (2013)
A 3D trenched-structure metal−insulator−metal (MIM) nanocapacitor array with an ultrahigh equivalent planar capacitance (EPC) of ∼300 μF cm−2 is demonstrated. Zinc oxide (ZnO) and aluminum oxide (Al2O3) bilayer dielectric is deposited on 1 μm high biomimetic silicon nanotip (SiNT) substrate using the atomic layer deposition method. The large EPC is achieved by utilizing the large surface area of the densely packed SiNT (∼5 × 1010 cm−2) coated conformally with an ultrahigh dielectric constant of ZnO. The EPC value is 30 times higher than those previously reported in metal−insulator−metal or metal−insulator−semiconductor nanocapacitors using similar porosity dimensions of the support materials.