Jea‐Gun Park

Four-level nonvolatile small-molecule 4F(2) memory cells were developed with a sandwiched device structure consisting of an upper Al electrode, upper small-molecule layer (Alq(3), aluminum tris(8-hydroxyquinoline)), Ni nanocrystals surrounded by NiO tunneling barrier, lower small-molecule layer, and bottom Al electrode. In particular, an in situ O(2)-plasma oxidation process following Ni evaporation was developed to produce uniformly stable 10 nm Ni nanocrystals surrounded by a NiO tunneling bar

Abstract It is presented for the first time nontoxic CuGaS 2 /ZnS quantum dots (QDs) with free‐self‐reabsorption losses and large Stokes shift (>190 nm) synthesized on an industrially gram‐scale as an alternative for Cd‐based energy‐downshift (EDS)‐QD layers. The QDs exhibit a typical EDS that absorbs only UV light (<407 nm) and emits the whole range of visible light (400–800 nm) with a high photoluminescence‐quantum yield of ≈76%. The straightforward application of these EDS‐QDs on the fr

Silicon solar cells mainly absorb visible light, although the sun emits ultraviolet (UV), visible, and infrared light. Because the surface reflectance of a textured surface with SiNX film on a silicon solar cell in the UV wavelength region (250-450 nm) is higher than ∼27%, silicon solar-cells cannot effectively convert UV light into photo-voltaic power. We implemented the concept of energy-down-shift using CdSe/ZnS core/shell quantum-dots (QDs) on p-type silicon solar-cells to absorb more UV lig

Through a chemical mechanical polishing (CMP) test using oxide and nitride blanket film wafers, we investigated the effect of adding an anionic surfactant to a ceria slurry, especially at very dilute concentrations (less than 0.2 wt%). The removal rate trend, which decreases with increasing surfactant concentration, was compared with the variation in the electrokinetic behavior of the ceria abrasives dispersed in the slurry. The removal rate transition did not coincide with the changes in the ze

The tunnel magnetoresistance (TMR) ratio of a cobalt-iron-boron (CoFeB)-based perpendicular-magnetic-tunnel-junction (p-MTJ) spin valve is extremely sensitive to both nanoscale Co2Fe6B2 free- and pinned-layer thicknesses. The TMR ratio peaks at a Co2Fe6B2 free-layer thickness of 1.05 nm, while it peaks at a Co2Fe6B2 pinned-layer thickness of 1.59 nm, achieving 104%. The amount of tantalum diffused into the MgO tunneling barrier (originated from a tantalum seed) decreases with increasing Co2Fe6B2

We correlate appearance of nano black spots (NBSs), optical stability and Goldschmidt tolerance factor (<italic>t</italic>) in mixed halide perovskite QDs.

We found that Cd0.5Zn0.5S-ZnS core (4.2 nm in diameter)-shell (1.2 nm in thickness) quantum dots (QDs) demonstrated a typical energy-down-shift (2.76-4.96 → 2.81 eV), which absorb ultra-violet (UV) light (250-450 nm in wavelength) and emit blue visible light (∼442 nm in wavelength). They showed the quantum yield of ∼80% and their coating on the SiNX film textured p-type silicon solar-cells enhanced the external-quantum-efficiency (EQE) of ∼30% at 300-450 nm in wavelength, thereby enhancing the s

The learning and inference efficiencies of an artificial neural network represented by a cross-point synaptic memristor array can be achieved using a selector, with high selectivity (I_on /I_off ) and sufficient death region, stacked vertically on a synaptic memristor. This can prevent a sneak current in the memristor array. A selector with multiple jar-shaped conductive Cu filaments in the resistive switching layer is precisely fabricated by designing the Cu ion concentratio

Recently, as an alternative solution for overcoming the scaling-down limitations of logic devices with design length of less than 3 nm and enhancing DRAM operation performance, 3D heterogeneous packaging technology has been intensively researched, essentially requiring Si wafer polishing at a very high Si polishing rate (500 nm/min) by accelerating the degree of the hydrolysis reaction (i.e., Si-O-H) on the polished Si wafer surface during CMP. Unlike conventional hydrolysis reaction accelerator

Nanoscale non-volatile CBRAM-cells are developed by using a CuO solid-electrolyte, providing a ∼10²memory margin, ∼3 × 10⁶endurance cycles, ∼6.63-years retention time at 85 °C, ∼100 ns writing speed, and MLC operation.

Flexible ultra-thin silicon solar cells with power-conversion-efficiency of 12.4 % implemented with an energy-down-shift layer show stable, flexible and twistable characteristics.

Flexible conductive-bridging random-access-memory (RAM) cells were fabricated with a cross-bar memory cell stacked with a top Ag electrode, conductive polymer (poly(n-vinylcarbazole): PVK), electrolyte (polyethylene oxide: PEO), bottom Pt electrode, and flexible substrate (polyethersulfone: PES), exhibiting the bipolar switching behavior of resistive random access memory (ReRAM). The cell also exhibited bending-fatigue-free nonvolatile memory characteristics: i.e., a set voltage of 1.0 V, a rese