Performance Improvement in E-Gun Deposited SiOx- Based RRAM Device by Switching Material Thickness Reduction

A performance improvement by reduction in switching material thickness in a e-gun deposited SiOx based resistive switching memory device was investigated. Reduction in thickness cause thinner filamentary path formation during ON-state by controlling the vacancy defects. Thinner filament cause lowering of operation current from 500 μA to 100 μA and also improves the reset current (from >400 μA to <100 μA). Switching material thickness reduction also cause the forming free ability in the device. All these electrical parametric improvements enhance the device reliability performances. The device show >200 dc endurance, >3-hour data retention and >1000 P/E endurance with 100 ns pulses.

Inscribing Difference: Code-Switching and the Metonymic Gap in Post-Colonial Literatures

In their seminal work The Empire Writes Back Ashcroft et al. (1989) identify code-switching between two or more codes in post-colonial literary texts as ‘the most common method of inscribing alterity’ (p.72). Ashcroft (2001) further develops the idea of installing cultural distinctiveness in the text and posits that, together with a wide range of other linguistic devices (e.g. neologisms, ethno-rhythmic prose), the use of code-switching – whether between the variants of the same language or between languages – has a metonymic function to inscribe cultural difference. In this chapter, I will examine the hybrid nature of post-colonial literary texts through the concepts of nativisation (Kachru, 1982a, 1982b, 1984, 1986, 1987, 1995) and indigenisation (Zabus, 1991, 2007). I will then focus on code-switching, adopting Myers-Scotton’s (1993) approach of matrix language vs. embedded language and considering that ‘EL [embedded language] material of any size, from a single morpheme or lexeme to several constituents, may be regarded as CS [code-switching] material’ (p.5). I will analyse examples of code-switching taken from modern Ghanaian English-language novels and short stories, and I will argue that a synecdochic relationship exists between the code-switched embedded language and the culture it originates from. I will contend that it is along the metonymic gap thus created by language variance that readers can be expected to be divided. I will briefly examine the types of authorial assistance that can be provided in order to make the text accessible to the reader, and I will illustrate, in Sperber and Wilson’s (1995) relevance theoretical framework, how different groups of readers cope with code-switched language left in the texts untranslated and/or unexplained. I will argue that by withdrawing assistance from the reader, the author makes it manifest that he concedes ‘the importance of meanibility’ (Ashcroft, 2001, p.76) and opts for the inscription of difference. I will conclude that the metonymic gap is not a simple bi-polar concept between coloniser and colonised culture but a multi-layered entity where the readers’ position in relation to the gap is indicative of their ability to interpret code-switched language unaided. Full appreciation of the writer’s meanings is shown by those readers who share both the writer’s cultural and linguistic experience. Other readers may be able to cross the metonymic gap to various degrees, but for them code-switched language will be the symbol of the writer’s difference of experience.

Investigation of switching uniformity in resistive memory via finite element simulation of conductive-filament formation

Herein, we present simulations of conductive filament formation in resistive random-access memory using a finite element solver. We consider the switching material, which is typically an oxide, as a two-phase material comprising low- and high-resistance phases. The low-resistance phase corresponds to a defective and conducting region with a high anion vacancy concentration, whereas the high-resistance phase corresponds to a non-defective and insulating region with a low anion-vacancy concentration. We adopt a phase variable corresponding to 0 and 1 in the insulating and conducting phases, respectively, and we change the phase variable suitably when new defects are introduced during voltage ramp-up for forming. Initially, some defects are embedded in the switching material. When the applied voltage is ramped up, the phase variable changes from 0 to 1 at locations wherein the electric field exceeds a critical value, which corresponds to the introduction of new defects via vacancy generation. The applied voltage at which the defects percolate to form a filament is considered as the forming voltage. Here, we study the forming-voltage uniformity using simulations, and we find that for typical planar-electrode devices, the forming voltage varies significantly owing to the stochastic location of the initial defects at which the electric field is “crowded.” On the other hand, a protruding electrode can improve the switching uniformity drastically via facilitating the deterministic location of electric-field crowding, which also supported by the reported experimental results.

Tuning the composition of conductive thermoplastics for stiffness switching and electrically activated healing

We introduce a class of stiffness-tuning polymer composites and carefully examine the influence of electrical activation and temperature on stiffness for a wide range of use cases. The composites are composed of a polycaprolactone matrix embedded with a percolating network of acetylene carbon black or multi-walled carbon nanotubes. This work builds on previous efforts with thermally activated stiffness-switching composites, which can enable reliable, high-switching-ratio stiffness-switching devices that are stiff in the passive state and are not confined to specific geometries or layouts. Here, we systematically investigate the effects of filler type, filler concentration, and matrix polymer molecular weight on the critical properties of the stiffness-switching material. Using these parameters, we develop a composition selection guide, which we use to construct three different stiffness-switching applications: a highly extensible stiffness-switching tendon, a large area moldable sheet, and an electrically healable mechanical fuse.