We demonstrated high-quality single crystalline a-plane undoped-gallium nitride grown on a nonpatterned r-plane sapphire substrate via metal-organic chemical vapor deposition. The effect of four different numbers of sandwiched strain-periodic AlN/GaN multilayers on the strain state, crystal quality, optical and electrical properties was investigated. Field emission scanning electron microscopy and atomic force microscopy showed that the surface morphology was improved upon insertion of 120 pairs of AlN/GaN thin layers with a root-mean-square roughness of 2.15 nm. On-axis X-ray ω-scan rocking curves showed enhanced crystalline quality: the full width at half maximum decreased from 1224 to 756 arcsec along the [0001] direction and from 2628 to 1360 arcsec along the [1-100] direction for a-GaN grown with 120 pairs of AlN/GaN compared to a-GaN without AlN/GaN pairs. Reciprocal space mapping showed that a-plane GaN with a high number of AlN/GaN pairs exhibits near-relaxation strain states. Room-temperature photoluminescence spectra showed that the sample with the highest number of AlN/GaN pairs exhibited the lowest-intensity yellow and blue luminescence bands, indicating a reduction in defects and dislocations. The a-plane InGaN/GaN LEDs with 120 pairs of SSPM-L AlN/GaN exhibited a significant increase (~ 250%) in light output power compared to that of LEDs without SSPM-L AlN/GaN pairs.
Over the past 20 years, rapid technological advancement in the field of microfluidics has produced a wide array of microfluidic point-of-care (POC) diagnostic devices for the healthcare industry. However, potential microfluidic applications in the field of nutrition, specifically to diagnose iron deficiency anemia (IDA) detection, remain scarce. Iron deficiency anemia is the most common form of anemia, which affects billions of people globally, especially the elderly, women, and children. This review comprehensively analyzes the current diagnosis technologies that address anemia-related IDA-POC microfluidic devices in the future. This review briefly highlights various microfluidics devices that have the potential to detect IDA and discusses some commercially available devices for blood plasma separation mechanisms. Reagent deposition and integration into microfluidic devices are also explored. Finally, we discuss the challenges of insights into potential portable microfluidic systems, especially for remote IDA detection.
A new 2D titanium carbide (Ti3C2), a low dimensional material of the MXene family has attracted remarkable interest in several electronic applications, but its unique structure and novel properties are still less explored in piezoelectric energy harvesters. Herein, a systematic study has been conducted to examine the role of Ti3C2 multilayers when it is incorporated in the piezoelectric polymer host. The 0.03 g/L of Ti3C2 has been identified as the most appropriate concentration to ensure the optimum performance of the fabricated device with a generated output voltage of about 6.0 V. The probable reasons might be due to the uniformity of nanofiller distribution in the polyvinylidene difluoride (PVDF) and the incorporation of Ti3C2 in a polymer matrix is found to enhance the β-phase of PVDF and diminish the undesired α-phase configuration. Low tapping frequency and force were demonstrated to scavenge electrical energy from abundant mechanical energy resources particularly human motion and environmental stimuli. The fabricated device attained a power density of 14 µW.cm-2 at 10.8 MΩ of load resistor which is considerably high among 2D material-based piezoelectric nanogenerators. The device has also shown stable electrical performance for up to 4 weeks and is practically able to store energy in a capacitor and light up a LED. Hence, the Ti3C2-based piezoelectric nanogenerator suggests the potential to realize the energy harvesting application for low-power electronic devices.