Language sentiment predicts changes in depressive symptoms.

The prevalence of depression is a major societal health concern, and there is an ongoing need to develop tools that predict who will become depressed. Past research suggests that depression changes the language we use, but it is unclear whether language is predictive of worsening symptoms. Here, we test whether the sentiment of brief written linguistic responses predicts changes in depression.

Correction: Causal role of the dorsolateral prefrontal cortex in modulating the balance between Pavlovian and instrumental systems in the punishment domain.

[This corrects the article DOI: 10.1371/journal.pone.

Causal role of the dorsolateral prefrontal cortex in modulating the balance between Pavlovian and instrumental systems in the punishment domain.

Previous literature suggests that a balance between Pavlovian and instrumental decision-making systems is critical for optimal decision-making. Pavlovian bias (i.e.

Computational models of subjective feelings in psychiatry.

Research in computational psychiatry is dominated by models of behavior. Subjective experience during behavioral tasks is not well understood, even though it should be relevant to understanding the symptoms of psychiatric disorders. Here, we bridge this gap and review recent progress in computational models for subjective feelings.

First-principles study on multiferroicity in the CrGeTe/InSe heterostructure influenced by finite strains.

Multiferroic materials that have more than two ferroicities at the same time have long been regarded as one of the strongest candidates to achieve technological breakthroughs in many kinds of nanodevice applications. Various types of multiferroic materials have been discovered and devised to date; however, related studies have been conducted without identifying a complete winner because each has a decisive disadvantage. The recently discovered multiferroicity in the 2D CrGeTe/InSe van der Waals heterostructure represents an important opportunity to create a new turning point in multiferroic research.

First principles study of oxygen vacancy activation energy barrier in zirconia-based resistive memory.

Unlike experimental measurements that appeared to be quite large activation barriers, oxygen vacancies in zirconia-based resistive random access memory (ReRAM) are believed to migrate with a fairly low energy barrier, and this discrepancy has not been noticed nor seriously questioned up to date. In this paper, we work on this problem by means of first-principles calculations categorizing all the possible migration pathways by crystallographic directions. From the results, it is found that the low activation energy of oxygen vacancy that is expected from the switching characteristic of the device is originated from +2q charged oxygen vacancies in a nanometer-sized filament migrating into a particular crystallographic direction of monoclinic zirconia.

The Parametric Study of Armchair Graphene Nanoribbon Field Effect Transistor by Non-Equilibrium Green's Function Method.

We have carried out a comprehensive parametric analysis on the potential performance of a graphene nanoribbon field effect transistor (GNRFET). We modeled the behavior of GNRFETs with nanometer width GNR channels to formulate a self-consistent, non-equilibrium Green's function (NEGF) scheme in conjunction with the Poisson equation and allow the GNRFET to operate as a switch. Based on the results, we propose a metric to compete with current silicon CMOS highperformance (HP) or low-power (LP) devices, explaining that this can vary widely depending on the GNRFET structure parameters.

Tuning of ionic mobility to improve the resistive switching behavior of Zn-doped CeO.

Correlation between the resistive switching characteristics of Au/Zn-doped CeO/Au devices and ionic mobility of CeO altered by the dopant concentration were explored. It was found that the ionic mobility of CeO has a profound effect on the operating voltages of the devices. The magnitude of operating voltage was observed to decrease when the doping concentration of Zn was increased up to 14%.

The origin of the exceptionally low activation energy of oxygen vacancy in tantalum pentoxide based resistive memory.

It is well known that collective migrations of oxygen vacancies in oxide is the key principle of resistance change in oxide-based resistive memory (OxRAM). The practical usefulness of OxRAM mainly arises from the fact that these oxygen vacancy migrations take place at relatively low operating voltages. The activation energy of oxygen vacancy migration, which can be inferred from the operational voltage of an OxRAM, is much smaller compared to the experimentally measured activation energy of oxygen, and the underlying mechanism of the discrepancy has not been highlighted yet.

Broad spectral responsivity in highly photoconductive InZnO/MoS heterojunction phototransistor with ultrathin transparent metal electrode.

An amorphous InZnO/MoS heterojunction-based phototransistor with excellent photoconductive gain and responsivity over the entire visible range has been demonstrated. The photogenerated current of the InZnO phototransistor at long light wavelength (>600 nm) was significantly improved by utilizing narrow bandgap MoS as the capping layer (1.3 eV).

Improved optical performance of multi-layer MoS phototransistor with see-through metal electrode.

In recent years, MoS has emerged as a prime material for photodetector as well as phototransistor applications. Usually, the higher density of state and relatively narrow bandgap of multi-layer MoS give it an edge over monolayer MoS for phototransistor applications. However, MoS demonstrates thickness-dependent energy bandgap properties, with multi-layer MoS having indirect bandgap characteristics and therefore possess inferior optical properties.

A study on mechanism of resistance distribution characteristics of oxide-based resistive memory.

Although oxide-based resistive switching memory (OxRAM) is one of the strong next-generation high capacity memory candidates, it has the critical disadvantage that deviations of resistance levels is too severe to be adopted as a high capacity memory device. More specifically, it is known that the larger on/off current ratios in multi-level operated OxRAMs, the greater deviation of resistance levels from the targeted values. However, despite the seriousness of the problem there has been no concrete theoretical study on the underlying mechanisms of the phenomenon.

Theoretical investigation of performance of armchair graphene nanoribbon field effect transistors.

In this paper, we theoretically investigate the highest possible expected performance for graphene nanoribbon field effect transistors (GNRFETs) for a wide range of operation voltages and device structure parameters, such as the width of the graphene nanoribbon and gate length. We formulated a self-consistent, non-equilibrium Green's function method in conjunction with the Poisson equation and modeled the operation of nanometer sized GNRFETs, of which GNR channels have finite bandgaps so that the GNRFET can operate as a switch. We propose a metric for competing with the current silicon CMOS high performance or low power devices and explain that this can vary greatly depending on the GNRFET structure parameters.

Quantitative analysis of charge trapping and classification of sub-gap states in MoS TFT by pulse I-V method.

The threshold voltage instabilities and huge hysteresis of MoS thin film transistors (TFTs) have raised concerns about their practical applicability in next-generation switching devices. These behaviors are associated with charge trapping, which stems from tunneling to the adjacent trap site, interfacial redox reaction and interface and/or bulk trap states. In this report, we present quantitative analysis on the electron charge trapping mechanism of MoS TFT by fast pulse I-V method and the space charge limited current (SCLC) measurement.

Determination of intrinsic mobility of a bilayer oxide thin-film transistor by pulsed I-V method.

Amorphous oxide semiconductor thin-film transistors (TFT) have been considered as outstanding switch devices owing to their high mobility. However, because of their amorphous channel material with a certain level of density of states, a fast transient charging effect in an oxide TFT occurs, leading to an underestimation of the mobility value. In this paper, the effects of the fast charging of high-performance bilayer oxide semiconductor TFTs on mobility are examined in order to determine an accurate mobility extraction method.

Effect of hydrogen on dynamic charge transport in amorphous oxide thin film transistors.

Hydrogen in zinc oxide based semiconductors functions as a donor or a defect de-activator depending on its concentration, greatly affecting the device characteristics of oxide thin-film transistors (TFTs). Thus, controlling the hydrogen concentration in oxide semiconductors is very important for achieving high mobility and minimizing device instability. In this study, we investigated the charge transport dynamics of the amorphous semiconductor InGaZnO at various hydrogen concentrations as a function of the deposition temperature of the gate insulator.

Pulse I-V characterization of a nano-crystalline oxide device with sub-gap density of states.

Understanding the charge trapping nature of nano-crystalline oxide semiconductor thin film transistors (TFTs) is one of the most important requirements for their successful application. In our investigation, we employed a fast-pulsed I-V technique for understanding the charge trapping phenomenon and for characterizing the intrinsic device performance of an amorphous/nano-crystalline indium-hafnium-zinc-oxide semiconductor TFT with varying density of states in the bulk. Because of the negligible transient charging effect with a very short pulse, the source-to-drain current obtained with the fast-pulsed I-V measurement was higher than that measured by the direct-current characterization method.

High mobility and high stability glassy metal-oxynitride materials and devices.

In thin film technology, future semiconductor and display products with high performance, high density, large area, and ultra high definition with three-dimensional functionalities require high performance thin film transistors (TFTs) with high stability. Zinc oxynitride, a composite of zinc oxide and zinc nitride, has been conceded as a strong substitute to conventional semiconductor film such as silicon and indium gallium zinc oxide due to high mobility value. However, zinc oxynitride has been suffered from poor reproducibility due to relatively low binding energy of nitrogen with zinc, resulting in the instability of composition and its device performance.

III-V compound semiconductors for mass-produced nano-electronics: theoretical studies on mobility degradation by dislocation.

As silicon-based electronics approach the limit of scaling for increasing the performance and chip density, III-V compound semiconductors have started to attract significant attention owing to their high carrier mobility. However, the mobility benefits of III-V compounds are too easily accepted, ignoring a harmful effect of unavoidable threading dislocations that could fundamentally limit the applicability of these materials in nanometer-scale electronics. In this paper, we present a theoretical model that describes the degradation of carrier mobility by charged dislocations in quantum-confined III-V semiconductor metal oxide field effect transistors (MOSFETs).

Dislocation scatterings in p-type Si(1-x)Ge(x) under weak electric field.

We present a theoretical model which describes hole mobility degradation by charged dislocations in p-type Si(1-x)Ge(x). The complete analytical expression of the dislocation mobility is calculated from the momentum relaxation time of hole carriers under weak electric field. The obtained dislocation mobility shows a T(3/2)/λ relation and is proportional to the germanium density x.

A plasma-treated chalcogenide switch device for stackable scalable 3D nanoscale memory.

Stackable select devices such as the oxide p-n junction diode and the Schottky diode (one-way switch) have been proposed for non-volatile unipolar resistive switching devices; however, bidirectional select devices (or two-way switch) need to be developed for bipolar resistive switching devices. Here we report on a fully stackable switching device that solves several problems including current density, temperature stability, cycling endurance and cycle distribution. We demonstrate that the threshold switching device based on As-Ge-Te-Si material significantly improves cycling endurance performance by reactive nitrogen deposition and nitrogen plasma hardening.

Modeling for multilevel switching in oxide-based bipolar resistive memory.

We report a physical model for multilevel switching in oxide-based bipolar resistive memory (ReRAM). To confirm the validity of the model, we conduct experiments with tantalum-oxide-based ReRAM of which multi-resistance levels are obtained by reset voltage modifications. It is also noticeable that, in addition to multilevel switching capability, the ReRAM exhibits extremely different switching timescales, i.

Nanometer-scale oxide thin film transistor with potential for high-density image sensor applications.

The integration of electronically active oxide components onto silicon circuits represents an innovative approach to improving the functionality of novel devices. Like most semiconductor devices, complementary-metal-oxide-semiconductor image sensors (CISs) have physical limitations when progressively scaled down to extremely small dimensions. In this paper, we propose a novel hybrid CIS architecture that is based on the combination of nanometer-scale amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) and a conventional Si photo diode (PD).