Polarization‐Dependent Electronic Transport in Graphene/Pb(Zr,Ti)O 3 Ferroelectric Field‐Effect Transistors (original) (raw)
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Advanced electronic materials, 2017
demonstrated tenfold improvement of charge carrier mobility in graphene-based field-effect transistors (FETs) when a conventional Si/SiO 2 substrate is replaced by an epitaxial lead zirconate titanate Pb(Zr,Ti)O 3 (PZT) film. Several other studies also showed that graphene-based FETs on ferroelectric substrates have nonvolatile memory properties. [3-8] While these studies demonstrate some practical characteristics of graphene-ferroelectric FETs (FeFETs), their electrical properties are not yet completely understood. In particular, these devices exhibit an unusual antihysteresis of electronic transport, which contradicts the hysteretic polarization dependence of PZT. [3-6] The electronic behavior of graphene FeFETs is schematically illustrated by Figure 1.
Journal of Experimental and Theoretical Physics, 2013
A quantitative model is developed to explain the antihysteretic behavior of the electrical resistivity of graphene on a ferroelectric Pb(Zr x Ti 1-x)O 3 substrate as a function of the gate voltage. The model takes into account the trapping of the electrons from the graphene layer by the states related to the graphene-fer roelectric interface. The finite energy gap of impurity states is also taken into account, which makes it possible to describe the well known experimental dependences, including an increase and the subsequent saturation of a "memory window" with the switching gate voltage. The obtained estimates can be important for creating next generation nonvolatile memory elements, which use the two stable values of electrical resistivity (one of them is attributed to logical "0" and the other, to "1") that result from the antihysteresis effect.
Combining graphene and organic ferroelectric for possible memory devices
Both ferroelectric materials and graphene attract plenty of scientific attention. Ferroelectrics are well known for their ability to maintain a polarization, which can be switched/reversed by an external electric field. Organic ferroelectrics (e.g. PVDF/TrFE) are of special interest because of their flexibility and durability. Graphene has already demonstrated its promise for future electronics. The two materials brought together give a new functionality of non-volatile memory. Proof-of-concept works have been already done, but only with exfoliated graphene. The main goal of this research is to study the possibility of making such devices using CVD graphene, in large amounts. In other words, we address the feasibility of this kind of graphene-based memory devices. This can be important for graphene-based electronics in the near future.
Influence of Domain Structure in Ferroelectric Substrate on Graphene Conductance (Authors' Review)
Ukrainian Journal of Physics
Review is devoted to the recent theoretical studies of the impact of domain structure of ferroelectric substrate on graphene conductance. An analytical description of the hysteresis memory effect in a field effect transistor based on graphene-on-ferroelectric, taking into account absorbed dipole layers on the free surface of graphene and localized states on its interfaces is considered. The aspects of the recently developed theory of p-n junctions conductivity in a graphene channel on a ferroelectric substrate, which are created by a 180-degree ferroelectric domain structure, are analyzed, and cases of different current regimes from ballistic to diffusion one are considered. The influence of size effects in such systems and the possibility of using the results for improving the characteristics of field effect transistors with a graphene channel, non-volatile ferroelectric memory cells with random access, sensors, as well as for miniaturization of various devices of functional nanoel...
Wafer-scale graphene/ferroelectric hybrid devices for low-voltage electronics
2011
Preparing graphene and its derivatives on functional substrates may open enormous opportunities for exploring the intrinsic electronic properties and new functionalities of graphene. However, efforts in replacing SiO$_{2}$ have been greatly hampered by a very low sample yield of the exfoliation and related transferring methods. Here, we report a new route in exploring new graphene physics and functionalities by transferring large-scale chemical vapor deposition single-layer and bilayer graphene to functional substrates. Using ferroelectric Pb(Zr$_{0.3}$Ti$_{0.7}$)O$_{3}$ (PZT), we demonstrate ultra-low voltage operation of graphene field effect transistors within pm1\pm1pm1 V with maximum doping exceeding 1013,mathrmcm−210^{13}\,\mathrm{cm^{-2}}1013,mathrmcm−2 and on-off ratios larger than 10 times. After polarizing PZT, switching of graphene field effect transistors are characterized by pronounced resistance hysteresis, suitable for ultra-fast non-volatile electronics.
Graphene-lead zirconate titanate optothermal field effect transistors
Applied Physics Letters, 2012
We have developed a pyroelectric field effect transistor (FET) based on a graphene-lead zirconate titanate (PZT) system. Under the incidence of a laser beam, the drain current can be increased or decreased depending on the direction of the polarization of the PZT substrate. The drain current sensitivity of the optothermal FET can reach up to 360 nA/mW at a drain field of 6.7 kV/m more than 5 orders of magnitude higher than that of the photogating transistors based on carbon nanotube on SiO2/Si substrate. Graphene is an excellent component for pyroelectric FET due to its high optical transparency and conductance.
Nonvolatile memory effects in hybrid devices of few-layer graphene and ferroelectric polymer films
2009
We report on the fabrication and electrical characterization of few-layer graphene (FLG) devices coated with a ferroelectric polymer layer of poly(vinylidene fluoride/trifluoroethylene) [P(VDF/TrFE)]. Highly stable and reliable resistance changes were observed under floating conditions, which were dependent on the back gate voltage applied beforehand. Nonvolatile memory functionality in the hybrid FLG-P(VDF/TrFE) devices is attributed to a remanent electric field induced by the ferroelectric polarization of the P(VDF/TrFE) layer. a)
Memtransistors Based on Nanopatterned Graphene Ferroelectric Field-Effect Transistors
Nanomaterials, 2020
The ultimate memristor, which acts as resistive memory and an artificial neural synapse, is made from a single atomic layer. In this manuscript, we present experimental evidence of the memristive properties of a nanopatterned ferroelectric graphene field-effect transistor (FET). The graphene FET has, as a channel, a graphene monolayer transferred onto an HfO2-based ferroelectric material, the channel being nanopatterned with an array of holes with a diameter of 20 nm.
arXiv (Cornell University), 2021
While technologically challenging, the integration of ferroelectric thin films with graphene spintronics potentially allows the realization of highly efficient, electrically tuneable, non-volatile memories through control of the interfacial spin-orbit driven interaction occuring at graphene/Co interfaces deposited on heavy metal supports. Here, the integration of ferroelectric Hf0.5Zr0.5O2 on graphene/Co/heavy metal epitaxial stacks is investigated via the implementation of several nucleation methods in atomic layer deposition. By employing in-situ Al2O3 as a nucleation layer sandwiched between Hf0.5Zr0.5O2 and graphene, the Hf0.5Zr0.5O2 demonstrates a remanent polarization (2Pr) of 19.2 µC/cm 2. Using an ex-situ, naturally oxidized sputtered Ta layer for nucleation, 2Pr could be controlled via the interlayer thickness, reaching maximum values of 28 µC/cm 2 with low coercive fields. Magnetic hysteresis measurements taken before and after atomic layer deposition show strong perpendicular magnetic anisotropy, with minimal deviations in the magnetization reversal pathways due to the Hf0.5Zr0.5O2 deposition process, thus pointing to a good preservation of the magnetic stack including single-layer graphene. X-ray diffraction measurements further confirm that the high-quality interfaces demonstrated in the stack remain unperturbed by the ferroelectric deposition and anneal. The proposed graphene-based ferroelectric/magnetic structures offer the strong advantages of ferroelectricity and ferromagnetism at room temperature, enabling the development of novel magneto-electric and non-volatile in-memory spin-orbit logic architectures with low power switching. 1