Temperature-insensitive reading of a flash memory cell

The temperature characteristics of the read current of the NOR embedded flash memory with a 1.5T-per-cell structure are theoretically analyzed and experimentally verified.We verify that for a cell programmed with a“10”state,the read current is either increasing,decreasing,or invariable with the temperature,essentially depending on the reading overdrive voltage of the selected bitcell,or its programming strength.By precisely controlling the programming strength and thus manipulating its temperature coefficient,we propose a new setting method for the reference cells that programs each of reference cells to a charge state with a temperature coefficient closely tracking tail data cells,thereby solving the current coefficient mismatch and improving the read window.

Performance enhancement of paper-based SERS chips by shell-isolated nanoparticle-enhanced Raman spectroscopy

Paper-based flexible surface-enhanced Raman scattering(SERS) chips have been demonstrated to have great potential for future practical applications in point-of-care testing(POCT) due to the potentials of massive fabrication, low cost, efficient sample collection and short signal acquisition time. In this work,common filter paper and Ag@Si O2 core-shell nanoparticles(NP) have been utilized to fabricate SERS chips based on shell-isolated nanoparticle-enhanced Raman spectroscopy(SHINERS). The SERS performance of the chips for POCT applications was systematically investigated. We used crystal violet as the model molecule to study the influence of the size of the Ag core and the thickness of the Si O2 coating layer on the SERS activity and then the morphology optimized Ag@Si O2 core-shell NPs was employed to detect thiram. By utilizing the smartphone as a miniaturized Raman spectral analyzer, high SERS sensitivity of thiram with a detection limit of 10^-9 M was obtained. The study on the stability of the SERS chips shows that a Si O2 shell of 3 nm can effectively protect the as-prepared SERS chips against oxidation in ambient atmosphere without seriously weakening the SERS sensitivity. Our results indicated that the SERS chips by SHINERS had great potential of practical application, such as pesticide residues detection in POCT.

Hole-transporting layer-free inverted planar mixed lead-tin perovskite-based solar cells

Mixed lead-tin （Pb-Sn） perovskites present a promising strategy to extend the light-harvesting range of perovskite-based solar cells （PSCs）. The use of electron- transporting layer or hole-transporting layer （HTL） is critical to achieve high device efficiency. This strategy, however, requires tedious layer-by-layer fabrication as well as high-temperature annealing for certain oxides. In this work, we fabricated HTL-free planar FAPb0.5Sn0.5I3 PSCs with the highest efficiency of 7.94%. High short- circuit current density of 23.13 mA/cm2 was attained, indicating effective charge extraction at the ITO/ FAPb0.5Sn0.5I3 interface. This finding provides an alter- native strategy to simplify the manufacture of single- junction or tandem PSCs.