Limiting the location where electron injection occurs at the cathode interface to a narrower region is the key factor for achieving a highly improved RS performance, which can be achieved by including Ru Nanodots. The development of a memory cell structure truly at the nanoscale with such a limiting factor for the electric-field distribution can solve the non-uniformity issue of future ReRAM.

The characteristics of the atomic layer deposition (ALD) of SrTiO3 (STO) films were examined for metal–insulator–metal capacitors, with Cp-based precursors Sr(iPr3Cp)2 and Cp*Ti(OMe)3 [Cp* = C5(CH3)5] employed as the Sr and Ti precursors, respectively. While the Sr precursor has a higher reactivity toward oxygen on the Ru substrate compared with another Ti precursor, with a 2,2,6,6-tetramethyl-3,5-heptanedionato ligand, which results in the highly Sr excessive STO film, the enhanced reactivity of the present Ti precursor suppressed the unwanted excessive incorporation of Sr into the film. A possible mechanism for the Sr overgrowth and retardation is suggested in detail. By controlling the subcycle ratio of SrO and TiO2 layers, stoichiometric STO could be obtained, even without employing a deleterious reaction barrier layer. This improved the attainable minimum equivalent oxide thickness of the Pt/STO/RuO2 capacitor to 0.43 nm, with acceptable leakage current density (∼8 × 10–8 A/cm2). This indicates an improvement of ∼25% in the capacitance density compared with previous work.

The effect of the top electrode (TE) on the ferroelectric properties and switching endurance of thin Hf0.5Zr0.5O2 films was examined. The TiN/Hf0.5Zr0.5O2/TiN capacitor can endure electric cycling up to 109 times, which is promising for the next‐generation memory. RuO2 TE was reduced during annealing due to the reactive TiN bottom electrode, resulting in the degradation of the ferroelectric properties and endurance. In addition, the endurance of the TiN/Hf0.5Zr0.5O2/TiN capacitors was optimized by changing the film thickness and the postannealing temperature. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Various array types of 1-diode and 1-resistor stacked crossbar array (1D1R CA) devices composed of a Schottky diode (SD) (Pt/TiO 2 /Ti/Pt) and a resistive switching (RS) memory cell (Pt/TiO 2 /Pt) are fabricated and their performances are investigated. The unit cell of the 1D1R CA device shows high RS resistance ratio ( ≈ 10 3 at 1.5 V) between low and high resistance state (LRS and HRS), and high rectifi cation ratio ( ≈ 10 5 ) between LRS and reverse-state SD. It also shows a short RS time of < 50 ns for SET (resistance transition from HRS to LRS), and ≈ 600 ns for RESET (resistance transition from LRS to HRS), as well as stable RS endurance and data retention characteristics. It is experimentally confi rmed that the selected unit cell in HRS (logically the "off " state) is stably readable when it is surrounded by unselected LRS (logically the "on" state) cells, in an array of up to 32 × 32 cells. The SD, as a highly non-linear resistor, appropriately controls the conducting path formation during the switching and protects the memory element from the noise during retention.

The degradation of ferroelectric (FE) properties of atomic layer deposited Hf0.5Zr0.5O2 films with increasing thickness was mitigated by inserting 1 nm-thick Al2O3 interlayer at middle position of the thickness of the FE film. The large Pr of 10 μC/cm2, which is 11 times larger than that of single layer Hf0.5Zr0.5O2 film with equivalent thickness, was achieved from the films as thick as 40 nm. The Al2O3 interlayer could interrupt the continual growth of Hf0.5Zr0.5O2 films, and the resulting decrease of grain size prevented the formation of non-ferroelectric monoclinic phase. The Al2O3 interlayer also largely decreased the leakage current of the Hf0.5Zr0.5O2 films.

A reliable and rapid manufacturing process of molybdenum disulfide (MoS ) with atomic-scale thicknesses remains a fundamental challenge toward its successful incorporation into high-performance nanoelectronics. It is imperative to achieve rapid and scalable production of MoS exhibiting high carrier mobility and excellent on/off current ratios simultaneously. Herein, inhibitor-utilizing atomic layer deposition (iALD) is presented as a novel method to meet these requirements at the wafer scale. The kinetics of the chemisorption of Mo precursors in iALD is governed by the reaction energy and the steric hindrance of inhibitor molecules. By optimizing the inhibition of Mo precursor absorption, the nucleation on the substrate in the initial stage can be spontaneously tailored to produce iALD-MoS thin films with a significantly increased grain size and surface coverage (>620%). Moreover, highly crystalline iALD-MoS thin films, with thicknesses of only a few layers, excellent room temperature mobility (13.9 cm V s ), and on/off ratios (>10 ), employed as the channel material in field effect transistors on 6″ wafers, are successfully prepared.

For the utilization of graphene in various energy storage and conversion applications, it must be synthesized in bulk with reliable and controllable electrical properties. Although nitrogen-doped graphene shows a high doping efficiency, its electrical properties can be easily affected by oxygen and water impurities from the environment. We here report that boron-doped graphene nanoplatelets with desirable electrical properties can be prepared by the simultaneous reduction and boron-doping of graphene oxide (GO) at a high annealing temperature. B-doped graphene nanoplatelets prepared at 1000 °C show a maximum boron concentration of 6.04 ± 1.44 at %, which is the highest value among B-doped graphenes prepared using various methods. With well-mixed GO and g-B2O3 as the dopant, highly uniform doping is achieved for potentially gram-scale production. In addition, as a proof-of-concept, highly B-doped graphene nanoplatelets were used as an electrode of an electrochemical double-layer capacitor (EDLC) and showed an excellent specific capacitance value of 448 F/g in an aqueous electrolyte without additional conductive additives. We believe that B-doped graphene nanoplatelets can also be used in other applications such as electrocatalyst and nano-electronics because of their reliable and controllable electrical properties regardless of the outer environment.

] This study was conducted to investigate efficient, systematic management of the Korean police and to examine the status and prevention of musculoskeletal disorders in Korean police officers. [Subjects and Methods] A survey of police officers (353 subjects) who visited the National Police Hospital from March 2013 to May 2013 was conducted using a structured questionnaire. [Results] The incidence of pain was 44.2% in the shoulder, 41.4% in the waist, 31.2% in the neck, 26.1% in the legs/foot, 16.7% in the hand/wrist/finger, and 14.7% in the arm/elbow. The comparative risk of the relevant part factors was analyzed by multiple regression analysis. The shoulder had a 4.87 times higher risk in police lieutenants compared with those under the rank of corporal and a 1.78 times higher risk in people with chronic diseases than those without chronic diseases. The arm/elbow had a 2.37 times higher risk in people who exercised than those who did not exercise and a 1.78 times higher risk in people with a chronic disease than those without chronic diseases. Generally, people with a chronic disease showed a higher risk than those without chronic diseases. [Conclusion] The results of this study could be useful as basic data for improvement of police welfare, specialized treatment for the health safety of the police, and efficient management of police resources.