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The 2D electron gas (2DEG) phenomenon that occurs at the amorphous thin film hetero‐oxide interface attracts great attention since it can avoid the use of a single‐crystal oxide substrate. In this study, the analysis of 2DEG at the interface of amorphous‐Al2O3 (a‐AO)/ZnO is conducted using ZnO as the bottom substrate, where both the oxide films are grown by atomic layer deposition. Having used Al(CH3)3 as the Al‐precursor for the a‐AO film growth on the previously grown ZnO film, its strong reducing power induces the 2DEG formation at the interface. As a result of the Hall measurement, the 2DEG at the a‐AO/ZnO interface shows sheet resistance of 2.7 × 104 Ω ▫−1 and Hall mobility of 8.4 cm2 V−1 s−1. Using angle‐resolved X‐ray photoelectron spectroscopy, the thickness of the 2DEG layer is calculated as 0.62 nm, which is ≈120% of the c‐axis of the wurtzite ZnO unit cell. The field‐effect transistor fabricated exhibits a threshold voltage of −2.4 V, sub‐threshold swing of 0.33 V dec−1, and on/off ratio of 9.4 × 106, which significantly outperforms similar devices from previous works. The outstanding operation of 2DEG at the interface of AO/ZnO as a channel presents a possibility for application to a 2D‐based integrated circuit. [ABSTRACT FROM AUTHOR]

The gate‐induced electrical instability of SnO thin‐film transistors (TFTs) with SiO2 and Al2O3/SiO2 gate dielectric layers is evaluated. The hysteresis voltage (Vhy) and threshold voltage (Vth) in the transfer characteristics of SnO TFTs depend on the sweep range and rate of gate voltage (VGS). The TFT with an Al2O3/SiO2 gate dielectric layer exhibit reduced Vhy and stable Vth compared with the device without an Al2O3 layer. The introduction of an Al2O3 layer between the SnO channel and the SiO2 layer suppresses the electron and hole trapping at the channel/dielectric interface and contains mobile oxygen vacancies that counteract the hole trapping effect. [ABSTRACT FROM AUTHOR]

In this study, we developed a novel method for preventing relay attacks over near field communication (NFC) using a simple interface. NFC provides standardized short-range contactless communication using one of the radio frequency identification communication channels. NFC-enabled mobile devices can exchange information in close proximity (within 4 cm). In particular, modern mobile phones have adopted NFC technology because of its promising functionalities, for example, mobile payments, Bluetooth pairing, and electronic keys. The distance limitation of NFC communication offers security advantages against passive or active attackers, but it is still vulnerable to relay attacks. During a relay attack, adversaries relay messages between two legitimate participants without any attempt at message modification. There is no requirement for knowledge of a cryptographic key or to share secrets with victims, therefore encrypting messages is not a solution that prevents relay attacks. We propose a new method for relay attack prevention, which uses a simple interface with only one button. In our scheme, the elapsed time of button pressing is used for verification. Our experimental results obtained using the proposed scheme demonstrated the accuracy of our method for verifying human users and the difficulties experienced by human attackers. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]