Rectifying electronic transport and the role of Fowler-Nordheim tunneling in Ag/PVDF/Au capacitor structures

Low‐frequency ferroelectric switching studies in PVDF thin films across Cu or (Ag/Cu)/PVDF/Cu capacitor structures

“…Previous structural studies of PVDF thin films upon Au, Ag, and Pt surfaces revealed that the βphase stabilizes only upon the Au interface. 25 In the current work, the monoclinic structure is found to be stable upon Cu surfaces without any electrical poling. The poling free phase formation is attributed to the in-situ annealed substrate temperature of 130 C, bottom electrode surface, and its seed polar grain formations.…”

“…The poling free phase formation is attributed to the in-situ annealed substrate temperature of 130 C, bottom electrode surface, and its seed polar grain formations. 24,25 The cross-sectional FE-SEM images of Cu-I, Cu-II, and Cu-III devices are shown in Figure 2 Table. 1. The surface microstructural AFM images of PVDF thin films deposited on Cu bottom electrodes measured in 10 μm 2 areas are represented in Figure 3.…”

“…The detailed deposition conditions to make PVDF thin films were described elsewhere. 24,25 Further, top electrodes of Cu and Ag/Cu layers were deposited using a metal mask (as shown in the Figure 1(b)). Ag films of 10 nm thickness at 0.33 nm/s rate using 320 V/0.08A were deposited on the Cu electrode.…”

“…[19][20][21] However, the preparation of polar phase PVDF thin films of less than 250 nm thickness found to be dependent upon in-situ annealing of the substrate and metal interfaces upon which it is deposited. [22][23][24][25][26] A typical spherulite microstructure is commonly treated as a signature for the noted polar β and γ phases. 15,27 In addition to the bottom electrode influence, the top electrode interface also plays a vital role in the observation of polar characteristic I-V curves.…”

“…Our recent work upon electronic transport across Ag/PVDF/Au devices revealed a rectified I-V transport rather than a ferroelectric switching behavior, although PVDF stabilizes in the polar phase on the Au surface. 25 Due to the high melting temperature and good device stack integrability of PVDF homopolymer thin films in comparison to its copolymers, homopolymer based thin films was considered potential for flexible ferroelectric thin film applications. As the electrode interfaces play a crucial role in deciding homopolymer's structure and its characteristic parameters (leakage currents, saturation polarization (P S ), remnant polarization (P r ) and coercive field (E C )), it is essential to comprehend the connection between thickness, electrode interfaces upon intrinsic polarization, coercive field, and polarization switching dynamics.…”