Search

Abstract Titanium oxides have partially filled or empty d orbital and are stable at various oxidation states with different structures and unique properties. Here, three kinds of titanium oxide thin films of hexagonal Ti 2 O metal, cubic TiO 1+ δ superconductor, and monoclinic γ-Ti 3 O 5 semiconductor, were successfully grown on α-Al 2 O 3 substrates by a pulsed laser deposition technique, through ablating a pure titanium target under different oxygen pressures. The electrical resistivities of these films increase with increasing oxygen content. The metallic behaviors of Ti bulk and Ti 2 O film can be described by the Bloch–Grüneisen formula, and the semiconducting behaviors of TiO 1 +δ films in normal state and γ-Ti 3 O 5 film obey the variable range hopping and the small polaron hopping conduction mechanisms, respectively. For titanium monoxide TiO 1+ δ (1.05 ≤ 1+ δ ≤ 1.17) films, increasing oxygen content is accompanied by an increase of disorder, a decrease of electron density of states at the Fermi level, and an enhancement of carrier localization, leading to a suppression of superconductivity. Graphical abstract Image 1 Highlights • Ti 2 O, TiO 1+ δ and Ti 3 O 5 thin films were grown by PLD using a pure titanium target. • Structures, compositions and transport properties can be tuned by oxygen contents. • The metallic hexagonal Ti 2 O single crystalline thin film was firstly prepared. [ABSTRACT FROM AUTHOR]

In this work, the damage caused by program/erase (P/E) operation in 3D NAND memory devices made of Metal-Al 2 O 3 -Nitride-Oxide-Semiconductor (MANOS) was examined. The damage caused by program and erase operations independently was intended to be identified and realized using several types of cycling stresses. Physical models were discussed to interpret that the anode hole could be responsible for the damage to the Al 2 O 3 -Nitride-Oxide (ANO) gate stacks. The tunnel oxide damage was caused by the erase operation and could be enhanced by a higher cycling temperature. This led to a faster program and a slower erase, and it demonstrated a strong correlation with retention and its active energy (Ea). On the other hand, program operation may merely be contributing to block oxide damage, with an invisible impact on erase efficiency and retention but a reduction in program efficiency. An optimized single pulse erase scheme was discussed. Not only can it reduce ANO damage and improve retention, but it can also decrease erase time. Furthermore, a feasible endurance acceleration method was discussed to save a lot of cycling time. [Display omitted] • Explains the impact of P/E operations on ANO damage. • High temperatures can accelerate cycling damage. • A quantitative improvement of the single pulse erase scheme is discussed. • An endurance acceleration method focuses on MANOS array intrinsic retention. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the first-of-its-kind electrochemical seismic sensor where, a liquid proof mass (e.g., electrolyte solution) was used as the sensing element to translate environmental vibrations into active ion imbalances between electrodes, and therefore producing electrical current outputs. Theoretical analysis and numerical simulations were conducted to confirm the feasibility of the device concept and the proposed micro seismic sensor was fabricated by conventional MEMS technologies. Device characterization based on a vibration table recorded a linear relationship between applied velocities and output voltage amplitudes with a calculated sensitivity of 274V/(m/s) (20–80Hz). The performance of the proposed micro device was compared with a commercially available macro counterpart (MET2003), indicating strong correlations of these two types of devices in response to random vibrations while the proposed micro seismic sensor was capable of producing a lower power spectrum compared to MET2003. In summary, the electrochemical micro seismic sensor developed in this study is featured with mass fabrication capabilities due to MEMS technologies, comparable performance and lower power spectrum compared to conventional electrochemical seismometers. This newly developed micro sensor can be potentially used in the field of seismology, enabling the ground motion monitoring to locate earthquakes, volcanic eruptions, and other seismic sources. [Copyright &y& Elsevier]