Flexible graphene-PZT ferroelectric nonvolatile memory

• Published in: Nanotechnology Vol. 24; no. 47; p. 475202
• Main Authors: Lee, Wonho, Kahya, Orhan, Toh, Chee Tat, Özyilmaz, Barbaros, Ahn, Jong-Hyun
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 29.11.2013; Institute of Physics
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Data storage; Devices; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electric potential; Exact sciences and technology; Ferroelectric materials; Ferroelectricity; Fullerenes and related materials; diamonds, graphite; Graphene; Lead zirconate titanates; Materials science; Mechanical and acoustical properties of condensed matter; Mechanical properties of nanoscale materials; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Specific materials; Voltage; CVD; Memory devices; Ferroelectric materials; Electrolyte solution; Graphene; Non volatile memory; Bending; Mechanical properties; PZT; Sol-gel process; Ferroelectric thin films
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/24/47/475202

We report the fabrication of a flexible graphene-based nonvolatile memory device using Pb(Zr0.35,Ti0.65)O3 (PZT) as the ferroelectric material. The graphene and PZT ferroelectric layers were deposited using chemical vapor deposition and sol-gel methods, respectively. Such PZT films show a high remnant polarization (Pr) of 30 μC cm−2 and a coercive voltage (Vc) of 3.5 V under a voltage loop over ±11 V. The graphene-PZT ferroelectric nonvolatile memory on a plastic substrate displayed an on/off current ratio of 6.7, a memory window of 6 V and reliable operation. In addition, the device showed one order of magnitude lower operation voltage range than organic-based ferroelectric nonvolatile memory after removing the anti-ferroelectric behavior incorporating an electrolyte solution. The devices showed robust operation in bent states of bending radii up to 9 mm and in cycling tests of 200 times. The devices exhibited remarkable mechanical properties and were readily integrated with plastic substrates for the production of flexible circuits.