Universal, giant and nonvolatile resistive switching is demonstrated for oxide tunnel junctions with ferroelectric PbZr0.2Ti0.8O3, ferroelectric BaTiO3, and paraelectric SrTiO3 tunnel barriers. The ...effects are caused by reversible migration of oxygen vacancies between the tunnel barrier and bottom La2/3Sr1/3MnO3 electrode. The switching process, which is driven by large electric fields, is efficient down to a temperature of 5 K.
In this study, we focused on the electrical and reliability characteristics of a ferroelectric diode (FE diode) composed of an InGaZnO (IGZO)/Hf<inline-formula> <tex-math ...notation="LaTeX">_{\text{x}}</tex-math> </inline-formula>Zr<inline-formula> <tex-math notation="LaTeX">_{\text{1-\text{x}}}</tex-math> </inline-formula>O<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> (HZO) stack by controlling the bulk and interface defect of IGZO. Initially, to achieve the high ON/OFF ratio, we reduced the bulk defects in the IGZO film during deposition by adjusting the oxygen partial pressure. This strategy effectively reduced the OFF-state leakage current in the high-resistance state (HRS), as demonstrated by current-voltage ( I -<inline-formula> <tex-math notation="LaTeX">\textit{V}\text{)}</tex-math> </inline-formula> characteristics and x -ray photoelectron spectroscopy (XPS) analysis. Subsequently, to enhance the endurance characteristics, we considered the application of microwave annealing (MWA) as an alternative to the conventional rapid thermal annealing (RTA) to decrease interface traps. Upon assessing interface trap densities, we confirmed an improved interface quality within double-layered structure. Consequently, the IGZO/HZO FE diode device exhibited a remarkable ON/OFF ratio of 4 <inline-formula> <tex-math notation="LaTeX">\times</tex-math> </inline-formula> 10<inline-formula> <tex-math notation="LaTeX">^{\text{5}}</tex-math> </inline-formula> and cycling endurance of 10<inline-formula> <tex-math notation="LaTeX">^{\text{10}}</tex-math> </inline-formula>, underlining the importance of defect management in device performance.
A new theoretical concept of an electrically controllable single-electron spin filter (polarizator) based on the exchange interaction in the system of interacting quantum dots or impurity atoms is ...proposed. The sign of the spin polarization of the current flowing through the device can be effectively controlled in two ways (i) by changing the applied bias and (ii) by tuning the tunnel coupling via an external gate. The minimal realization involves three bound state levels coupled to the contact leads. One of these levels is occupied by a single electron with a certain spin and the two-electron occupation is prohibited by a strong on-site Coulomb repulsion. Interestingly, while the spin polarization of this state is fixed, the sign of the single-electron current spin polarization flowing between the contacts through two consistent bound state levels can be switched.
•A new theoretical concept of an electrically controllable single-electron spin filter is proposed.•The presence of both exchange interaction and on-site Coulomb repulsion is important.•Spin-filtering can be organized by changing the applied bias or by tuning the tunnel coupling via an external gate.•The considered phenomena are sensitive to electron correlations giving an experimental access to the many-body phenomena.•The obtained results open the possibility for precise control of tunneling current spin polarization.
In this paper, a physics-based DC compact model for Schottky barrier field-effect transistors at deep cryogenic temperatures is presented. The model uses simplified tunneling equations at ...temperatures of ϑ≈0K in order to calculate the field emission injection current at the device’s Schottky barriers. Additionally, an empirical expression for including resonant tunneling effects is introduced. The compact model is also compared to and verified by measurements performed on ultra-thin body and buried oxide SOI Schottky barrier field-effect transistors and is able to capture the signature of resonant tunneling effects in the transfer characteristics.
•Presents a DC compact model for Schottky barrier field-effect transistors.•Model is physics-based, closed-form and for deep cryogenic temperature environment.•Field emission current at the Schottky barrier is calculated.•Verification is done on measurements.
The fabrication of large‐area vertical junctions with a molecular spin‐crossover complex displaying concerted changes of spin degrees of freedom and charge‐transport properties is reported. ...Fabricated devices allow spin‐state switching in the spin‐crossover layer to be triggered and probed by optical means, while detecting associated changes in electrical resistance in the junctions.
The wxAMPS program is an update of the popular solar cell simulation tool AMPS (Analysis of Microelectronic and Photonic Structures). The user interface of wxAMPS uses a cross-platform library and ...provides quick data entry and improved visualization. Beyond the original AMPS kernel, wxAMPS incorporates two tunneling models and a new algorithm combining the Newton and Gummel methods. The incorporation of a trap-assisted tunneling model makes more precise simulation of multi-junction solar cells possible. The combined Newton and Gummel method solutions improve stability of the code and permit both tunneling models to function well within the algorithm. Based on the option for an unlimited number of layers in the simulation, modeling graded solar cells can be implemented easily in wxAMPS.
► We present a new solar cell simulation tool, wxAMPS. ► wxAMPS possesses a friendly user interface and supports quick data entry and convenient results analysis. ► Two tunneling models have been incorporated and solved by a new algorithm. ► wxAMPS provides full capabilities for modeling graded and tandem solar cells.
Field emission current exponentially depends on the work function of a cold surface. We consider the role of work function distribution on tunneling current. The work function distribution can arise ...due to nano-scale inhomogeneities of the surface as well as for collection of nano-particles with size distribution. We consider both Gaussian distribution as well as log-normal distribution. For Gaussian distribution, the field emission current, Jav, averaged over work function distribution shows Gaussian dependence, Jav∝exp(ασ2), where σ is the width of the work function distribution and α is a fitting parameter. For log-normal distribution, Jav shows compressed exponential behavior, Jav∝exp(γσn), where the exponent n>1 is a non-universal parameter. We also study in detail field emission current for various electric field strength applied to systems with high density, characterized by Fermi energy, EF≫Φ, Φ being the work function of the system as well as systems with low density characterized by EF≪Φ.
Passive intermodulation (PIM) by metal contacts limits the bandwidth and capacity of radio links used in mobile and satellite communications. In this work, we investigate the effect of nonlinearities ...in metal-insulator-metal (MIM) contacts and their effects on PIM generation. An analytical expression is obtained for the tunneling current density which has an error of <inline-formula> <tex-math notation="LaTeX">\sim</tex-math> </inline-formula>1.6% in the case of a very thin insulator and low voltages in MIM junctions. The presented analytical model of the contact surfaces with the fractal geometry is used to simulate PIM products of third-order (PIM3) and fifth-order (PIM5) versus the contact resistance and applied pressure. The simulation results are validated experimentally by an open-ended rectangular coaxial structure with a slotted enclosure. The measurement results demonstrate that the presented model predicts the PIM with a mean error of about 4.8 dB when the contact pressure varies from 0.5 to 1.7 MPa.
We propose a stochastic memristor utilizing ultrathin native-SiOx films (∼2.7 nm) and dynamic Ag nanoclusters for constructing physical unclonable function (PUF) hardware. The atomically thin solid ...electrolyte allows for quantum-mechanical tunneling current at high resistance states, which exponentially increases the entropy between separated devices. This results in good uniformity (54.4%), uniqueness (53.7%), and reliability (98.75%) for the prototype native-SiOx mem-PUF array. Furthermore, the proposed device demonstrates reconfigurability for key refreshing and passes all 15 National Institute of Science and Technology (NIST) tests, verifying the high randomness of the generated bits. Overall, this work highlights the potential of the ultrathin native-SiOx memristor for PUF applications.
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