Induced pH-dependent shift by local surface plasmon resonance in functionalized gold nanorods

Localized surface plasmon resonance (LSPR) spectroscopy of metallic nanoparticles is a powerful tool for chemical and biological sensing experiments. In this study, we observed LSPR shifts of 11-mercaptoundecanoic acid modified gold nanorods (GNR-MUA) for the pH range of 6.41 to 8.88. We proposed a mechanism involving changes of the dipole moment after protonation/deprotonation carboxylic groups of 11-mercaptoundecanoic acid (MUA) which plays an important role by modulating LSPR around the functionalized GNR. Such a stable and easily prepared GNR-MUA has potential to become one of the most efficient and promising pH nanosensors to study intra- or extra-cellular pH in a wide range of chemical or biological systems.     

嵌入式存储器测试

随着存储器需求的增加以及制造技术的进步,嵌入式存储器在SOC系统中的地位越来越重要。与传统的分立存储器件测试相比,嵌入式存储器的测试呈现出新的挑战。本文试图全面叙述嵌入式存储器的各种结构,并介绍各种DFT（可测性设计）测试技术,如SCAN〔扫描〕、MBIST（存储器内建自测试）以及BISR（内建自修复）。     

A Double-Spacer I-MOS Transistor With Shallow Source Junction and Lightly Doped Drain for Reduced Operating Voltage and Enhanced Device Performance

In this letter, a double-spacer (DS) design is utilized for the formation of shallow source and lightly doped drain to further optimize the impact-ionization MOS (I-MOS) transistor structure. The breakdown voltage V_BD needed for avalanche breakdown is lowered due to the shallow source extension. With the formation of the lightly doped drain extension, the impact of drain bias on breakdown voltage, and hence, the threshold voltage V_T is also reduced. The DS I-MOS is fabricated and characterized. Detailed analysis and physical explanation of the impact of drain/gate bias on the device characteristics are provided. Compared to the conventional I-MOS transistor, the shallow source extension reduces the breakdown voltage [drain-induced breakdown voltage lowering (DIBVL)] by 0.3-0.6 V, and the lightly doped drain extension reduces the DIBVL up to 0.17 V/V. In addition, excellent subthreshold swing and good device performance are achieved.     

Evaluation on Influencing Factors of Board-Level Drop Reliability for Chip Scale Packages (Fine-Pitch Ball Grid Array)

Board-level drop testing is an effective method to characterize the solder joint reliability performance of miniature handheld products. In this study, drop test of printed circuit boards (PCBs) with a four-screw support condition was conducted for a 15 mm times 15 mm fine-pitch ball grid array (FBGA) package assembly with solder ball compositions of 36Pb-62Sn-2Ag and Sn-4Ag-0.5Cu on printed circuit board (PCB) surface finishes of organic solderability preservative, electroless nickel immersion gold, and immersion tin. Finite element modeling of the FBGA assembly was performed to study the stress-strain behavior of the solder joints during drop test. The drop test results revealed a strong influence of different intermetallic compound formation on soldered assemblies drop durability. The lead-based solder supersedes the lead-free composition regardless of the types of surface finish. Joints on organic solderability preservative were found to be strongest for each solder type. Other factors affecting drop reliability such as component location on the board and thermal cycling aging effects are reported. Finite element modeling results showed that a solder joint is more prone to failure on the PCB side, and the predicted solder joint stresses are location dependent. Predicted failure sites based on simulation results are consistent with experimental observations.     

Nanostructured Silicon Anodes for Lithium Ion Rechargeable Batteries

Rechargeable lithium ion batteries are integral to today's information‐rich, mobile society. Currently they are one of the most popular types of battery used in portable electronics because of their high energy density and flexible design. Despite their increasing use at the present time, there is great continued commercial interest in developing new and improved electrode materials for lithium ion batteries that would lead to dramatically higher energy capacity and longer cycle life. Silicon is one of the most promising anode materials because it has the highest known theoretical charge capacity and is the second most abundant element on earth. However, silicon anodes have limited applications because of the huge volume change associated with the insertion and extraction of lithium. This causes cracking and pulverization of the anode, which leads to a loss of electrical contact and eventual fading of capacity. Nanostructured silicon anodes, as compared to the previously tested silicon film anodes, can help overcome the above issues. As arrays of silicon nanowires or nanorods, which help accommodate the volume changes, or as nanoscale compliant layers, which increase the stress resilience of silicon films, nanoengineered silicon anodes show potential to enable a new generation of lithium ion batteries with significantly higher reversible charge capacity and longer cycle life.     

High‐Temperature Ionic Epitaxy of Halide Perovskite Thin Film and the Hidden Carrier Dynamics

High‐temperature vapor phase epitaxy (VPE) has been proved ubiquitously powerful in enabling high‐performance electro‐optic devices in III–V semiconductor field. A typical example is the successful growth of p‐type GaN by VPE for blue light‐emitting diodes. VPE excels as it controls film defects such as point/interface defects and grain boundary, thanks to its high‐temperature processing condition and controllable deposition rate. For the first time, single‐crystalline high‐temperature VPE halide perovskite thin film has been demonstrated—a unique platform on unveiling previously uncovered carrier dynamics in inorganic halide perovskites. Toward wafer‐scale epitaxial and grain boundary‐free film is grown with alkali halides as substrates. It is shown the metal alkali halides could be used as universal substrates for VPE growth of perovskite due to their similar material chemistry and lattice constant. With VPE, hot photoluminescence and nanosecond photo‐Dember effect are revealed in inorganic halide perovskite. These two phenomena suggest that inorganic halide perovskite could be as compelling as its organic–inorganic counterpart regarding optoelectronic properties and help explain the long carrier lifetime in halide perovskite. The findings suggest a new avenue on developing high‐quality large‐scale single‐crystalline halide perovskite films requiring precise control of defects and morphology.     

Patient skin dosimetry in haemodynamic and electrophysiology interventional cardiology

With the increase in number and complexity of interventional cardiology (IC) procedures, it is important to monitor skin dose in order to decrease skin injuries. This study investigated radiation doses for patients undergoing IC procedures, compare results with the literature and define a local dose-area product trigger level for operators to identify situations likely to exceed the threshold for transient skin erythema of 2 Gy. Dosimetric data were collected for 77 haemodynamic and 90 electrophysiological procedures. Mean maximum local skin doses (MSDs) were 0.28 Gy for coronary angiography, 1.03 Gy for percutaneous transluminal coronary angioplasty (PTCA), 0.03 Gy for pacemaker insertion, 0.17 Gy for radiofrequency ablation for nodal tachycardia, 0.10 Gy for WPW and 0.22 Gy for atrial flutter. Since MSD values for the other procedures were well below the deterministic effect limit, a trigger level of 140 Gy cm2 was derived for PTCA procedures alone.     

1T‐Phase WS2 Protein‐Based Biosensor

Metallic 1T‐phase transition metal dichalcogenides have been recognized for their desirable properties like high surface‐to‐volume ratio, high conductivity, and capacitive behavior, making them outstanding for catalytic and sensing applications. Herein, a hydrogen peroxide (H₂O₂) biosensor is constructed by the immobilization of hemoglobin (Hb) on 1T‐phase WS₂ (1T‐WS₂) sheets, and entrapment by glutaraldehyde. 1T‐WS₂ not only displays electrocatalytic activity toward the reduction of H₂O₂ but also provides a high surface‐to‐volume ratio and conductive platform for the immobilization of Hb and facilitation of its electron transfer to the electrode surface. The advantageous role of 1T‐phase WS₂ is further demonstrated for the construction of a heme‐based H₂O₂ biosensor compared to its 1T‐phase MoS_2, MoSe₂, and WSe₂ counterparts. Synergistic interactions between 1T‐WS₂ and Hb result in a H₂O₂ biosensor with high analytical performance in terms of wide range, sensitivity, selectivity, reproducibility, repeatability, and stability. These findings have profound impact in the research fields of electrochemical sensing and biodiagnostics.