Metastable m -NiSe ₂ /CFC films are realized to promote chemisorption, accelerate reaction kinetics and suppress the shuttle effect of lithium polysulfides, resulting in high rate capability and superior cycling stability for lithium–sulfur batteries.

Great improvement in crystal quality of a-plane (non-polar) GaN has been achieved using a simple but effective overgrowth technique based on self-organized nano-masks. This has been confirmed by a massive reduction in full width at half maximum of x-ray diffraction rocking curves measured along both symmetrical and asymmetrical directions. Taking the advantage of utilising the nano-masks, a quick coalescence with a thickness of less than 1 μm has been obtained, which is much less than that using any conventional overgrowth techniques. The dislocation density has been significantly reduced by more than one order magnitude compared with a standard a-plane GaN layer on sapphire. An InGaN/GaN multiple quantum well (MQW) structure grown on the high quality a-plane GaN has demonstrated an enhancement with a factor of 7 in optical efficiency, compared with a similar MQW structure grown on a standard c-plane GaN layer. The excitation-power dependent photoluminescence measurements have confirmed that the a-plane InGaN/GaN MQW structure does not suffer from quantum-confined Stark effect any more.

This study demonstrated InGaN-based amber micro-light-emitting diodes (μLEDs) with varying Al contents of 2%, 5%, and 16% in barriers. The μLEDs with Al _0.05 GaN in barriers exhibited the highest on-wafer wall-plug efficiency due to the good material quality and optimal energy band engineering for carrier injection. We fabricated μLEDs with diameters ranging from 60 to 10 μm using the optimal epi-structure. The forward voltage was 2.15 V at 1 A/cm ² , a significantly lower value compared to others. The external quantum efficiency and wall-plug efficiency of the packaged μLEDs with a diameter of 10 μm are 4.8% and 4% at 1 A/cm ² , respectively. The slight decrease in efficiency of 10-μm μLEDs can be attributed to the sidewall effect, which was confirmed by photoluminescent and lifetime mapping.

This work reports a high-performance InGaN-based red-emitting LED with a strain-release interlayer (SRI) consisting of an InGaN stress-release layer (SRL) and an AlN dislocation confinement layer (DCL) in unintentionally doped GaN (u-GaN). The SRL introduces a tensile strain which could decrease the in-plane compressive stress of the u-GaN layer, while the DCL could reduce the dislocation density and thus improve the crystal quality of the u-GaN layer. Consequently, a high-efficiency InGaN-based red-emitting LED with a peak wavelength of 651 nm and an external quantum efficiency of 6.04% is realized. In addition, the room-temperature photoluminescence (PL) mapping emission wavelength is uniform across a 4-inch wafer with a standard deviation of 3.3 nm. Therefore, the proposed SRI offers good potential for mass-producing high-performance and long-wavelength InGaN-based red-emitting LEDs.