Boosting Monolayer Transition Metal Dichalcogenides Growth by Hydrogen-Free Ramping during Chemical Vapor Deposition.

The controlled vapor-phase synthesis of two-dimensional (2D) transition metal dichalcogenides (TMDs) is essential for functional applications. While chemical vapor deposition (CVD) techniques have been successful for transition metal sulfides, extending these methods to selenides and tellurides often faces challenges due to uncertain roles of hydrogen (H2) in their synthesis. Using CVD growth of MoSe2 as an example, this study illustrates the role of a H2-free environment during temperature ramping in suppressing the reduction of MoO3, which promotes effective vaporization and selenization of the Mo precursor to form MoSe2 monolayers with excellent crystal quality. As-synthesized MoSe2 monolayer-based field-effect transistors show excellent carrier mobility of up to 20.9 cm2/(V·s) with an on-off ratio of 7 × 107. This approach can be extended to other TMDs, such as WSe2, MoTe2, and MoSe2/WSe2 in-plane heterostructures. Our work provides a rational and facile approach to reproducibly synthesize high-quality TMD monolayers, facilitating their translation from laboratory to manufacturing.

Rational Design of Phase-Engineered WS2/WSe2 Heterostructures by Low-Temperature Plasma-Assisted Sulfurization and Selenization toward Enhanced HER Performance.

Efficient hydrogen generation from water splitting underpins chemistry to realize hydrogen economy. The electrocatalytic activity can be effectively modified by two-dimensional (2D) heterostructures, which offer great flexibility. Furthermore, they are useful in enhancing the exposure of the active sites for the hydrogen evolution reaction. Although the 1T-metallic phase of the transition metal dichalcogenides (TMDs) is important for the hydrogen evolution reaction (HER) catalyst, its practical application has not yet been much utilized because of the lack of stability of the 1T phase. Here, we introduce a novel approach to create a 1T-WS2/1T-WSe2 heterostructure using a low-temperature plasma-assisted chemical vapor reaction (PACVR), namely plasma-assisted sulfurization and plasma-assisted selenization processes. This heterostructure exhibits superior electrocatalytic performance due to the presence of the metallic 1T phase and the beneficial synergistic effect at the interface, which is attributed to the transfer of electrons from the underlying WS2 layer to the overlying WSe2 layer. The WS2/WSe2 heterostructure catalyst demonstrates remarkable performance in the HER as evidenced by its small Tafel slope of 57 mV dec-1 and exceptional durability. The usage of plasma helps in replacing the top S atoms with Se atoms, and this ion bombardment also increases the roughness of the thin film, thus adding another factor to enhance the HER performance. This plasma-synthesized low-temperature metallic-phase heterostructure brings out a novel method for the discovery of other catalysts.

Rational design of comb-like 1D-1D ZnO-ZnSe heterostructures toward their excellent performance in flexible photodetectors.

One-dimensional (1D) Zn-based heterostructures have attracted considerable interest in the field of photodetection because of their tunable properties, flexibility, and unique optoelectronic properties. However, designing 1D multi-component Zn-based heterostructures for advanced photodetectors is still a great challenge. Herein, comb-like 1D-1D ZnO-ZnSe heterostructures with ZnO and ZnSe nanowires (NWs) comprising the shaft and teeth of a comb are reported. The length of the ZnO NWs can be modulated in the range of 300-1200 nm. Microstructural characterizations confirm that the 1D heterostructure clearly shows the spatial distribution of individual components. The well-designed structure displays an extended broadband photoresponse and higher photosensitivity than pure ZnSe NWs. Furthermore, ZnSe NWs with an appropriate length of ZnO branches show increased photoresponses of 3835% and 798% compared to those of pure ZnSe NWs under green and red-light irradiation, respectively. In addition, the integrated flexible photodetector presents excellent folding endurance after 1000 bending tests. This well-designed structure has significant potential for other 1D-based semiconductors in optoelectronic applications.

Solution-Processed Flexible Temperature Sensor Array for Highly Resolved Spatial Temperature and Tactile Mapping Using ESN-Based Data Interpolation.

High-performance flexible temperature sensors are crucial in various technological applications, such as monitoring environmental conditions and human healthcare. The ideal characteristics of these sensors for stable temperature monitoring include scalability, mechanical flexibility, and high sensitivity. Moreover, simplicity and low power consumption will be essential for temperature sensor arrays in future integrated systems. This study introduces a solution-based approach for creating a V2O5 nanowire network temperature sensor on a flexible film. Through optimization of the fabrication conditions, the sensor exhibits remarkable performance, sustaining long-term stability (>110 h) with minimal hysteresis and excellent sensitivity (∼-1.5%/°C). In addition, this study employs machine learning techniques for data interpolation among sensors, thereby enhancing the spatial resolution of temperature measurements and adding tactile mapping without increasing the sensor count. Introducing this methodology results in an improved understanding of temperature variations, advancing the capabilities of flexible-sensor arrays for various applications.

P-side-up thin-film AlGaInP-based light emitting diodes with direct ohmic contact of an ITO layer with a GaP window layer.

A twice wafer-transfer technique can be used to fabricate high-brightness p-side-up thin-film AlGaInP-based light-emitting diodes (LEDs) with an indium-tin oxide (ITO) transparent conductive layer directly deposited on a GaP window layer, without using postannealing. The ITO layer can be used to improve light extraction, which enhances light output power. The p-side-up thin-film AlGaInP LED with an ITO layer exhibited excellent performance stability (e.g., emission wavelength and output power) as the injection current increased. This stability can be attributed to the following factors: 1) Refractive index matching, performed by introducing ITO between the epoxy and the GaP window layer enhances light extraction; and 2) The ITO layer is used as the current spreading layer to reduce the thermal accumulation in the epilayers.

Treatment of unstable lumbar intervertebral disc herniation by modified lamina osteotomy replantation / 中国骨伤

<p><b>OBJECTIVE</b>To evaluate the clinical effects of the modified lamina replantation for the treatment of unstable lumbar intervertebral disc herniation.</p><p><b>METHODS</b>From March 2009 to August 2011,63 patients with unstable lumbar intervertebral disc herniation were treated by discectomy, interbody fusion, pedicle screw fixation, and modified lamina replantation. There were 33 males and 30 females with an average age of 48.4 years old ranging from 22 to 68 years old. The average duration of disease was 38.8 months ranging from 3 months to 13 years. All patients had lower back and leg pains. X-ray,CT and MR results showed unstable lumbar intervertebral disc herniation. Preoperative and postoperative ODI, JOA scores, complication incident rates,radiographic healing rates,and lower back and leg pain recurrence rates were observed and recorded.</p><p><b>RESULTS</b>Sixty-two incisions were healed at first stage, 1 at second stage. There were no complications such as deep vein thrombosis, intervertebral infection and so on. Sixty-one patients were followed up for more than one year, and the mean duration was 33 months. Nerve and dural injury occurred in 2 patients and 1 patient respectively. One-year fusion happened in 58 patients while the recurrence of lower back pain and leg pain after 1 year were noted in 4 patients and 1 patient respectively. ODI, and JOA scores were respectively re-assessed at 2 weeks, 6 months and 1 year after the operation, and the results showed a significant difference from the preoperative scores (P < 0.05).</p><p><b>CONCLUSION</b>Modified lamina replantation for unstable lumbar intervertebral disc herniation showed lower rates of dural and nerve damage, as well as a higher lamina healing rate, lower back and leg pain recovery rate, and a better clinical score. It is a safe and efficient operation choice for lumbar spine surgery.</p>

Physicochemical and sustained drug release properties of calcium phosphate cement/amifostine/cisplatin complex and its effect in repairing bone defect due to tumor resection in rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the feasibility of using calcium phosphate cement/amifostine complex as an new filling material for repairing bone defect caused by tumor resection.</p><p><b>METHODS</b>Calcium phosphate cement (CPC)/cisplatin/amifostine complex was prepared at the mass ratio of 1000:2:5. The setting time, mechanical strength, and porosity of the complex were determined, and scanning electron microscopy and assessment of sustained drug release and inhibitory effect against osteosarcoma cells were carried out. The degradation of the material and new bone ingrowth were also observed in a rabbit model of femoral bone defect.</p><p><b>RESULTS</b>The setting time, strength, and porosity, appearances under scanning electron microscope, and sustained drug release properties of CPC/cisplatin/amifostine complex were identical to those of CPC, and the integration of amifostine in the complex did not affect the cytotoxicity of cisplatin against the osteosarcoma cells. Pathological evidences of the degradation of the material and new bone ingrowth into the material were observed with the passage of time following its implantation into the bone defect in rabbits.</p><p><b>CONCLUSION</b>The CPC/cisplatin/amifostine complex can be used as a filling material for repairing bone defect caused by tumor resection and eliminating the residual tumor cells in rabbits.</p>