High-resolution structural mapping and single-domain switching kinetics in 2D-confined ferroelectric nanodots for low-power FeRAM
Ferroelectric nanostructures have received much attention because they can be used for the next generation of ferroelectric random-access memory (FeRAM) in flexible electronic devices. Manipulation of domain reversal in ferroelectric nanostructures is extremely important, but rarely studied. Herein, we present generic and reusable fabrication of 2D-confined P(VDF-TrFE) nanodots with an integration density of up to 4 Gbit per inch2, and then investigate the structural maps and the corresponding domain switching kinetics of P(VDF-TrFE) nanodots by atomic force microscope-based (AFM-based) technology. Meanwhile, their storage features, such as precise programmability and data stability, are well characterized by piezoresponse force microscopy (PFM). Remarkably, the ferroelectric crystals in single-confined P(VDF-TrFE) nanodots simultaneously aligned in a plane over the whole patterned region. 2D-confined P(VDF-TrFE) 50 : 50 nanodots has high-temperature ferroelectric (HT FE) phase with all-trans conformations, which endows them with excellent memory characteristics, such as a low operating voltage of 3 V, a short domain nucleation of 100 ms (by V = 10 V), a fast domain growth, an excellent writing–erasing repeatability, and a long retention time. Compared with normal ferroelectric materials, like P(VDF-TrFE) 70 : 30, approximately 150% ratio of energy loss and a 5-fold duration for domain nucleation can be saved. Especially, written domains were well confined in the P(VDF-TrFE) 50 : 50 nanodots, which attains precise programmability on a single nanodot. Our systematic study provides an alternative route for the fabrication of ferroelectric nanostructures that are worth considering for the next generation of flexible FeRAM in all-organic nanoelectronic devices.