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We propose a GaN-based superjunction current-aperture vertical electron transistor (CAVET) with a dipole layer (DL-SJ CAVET) and demonstrated two-dimensional numerical simulations by Silvaco-Atlas. The dipole layer (DL) formed by Al0.1Ga0.9N is attached to the Al0.15Ga0.85N barrier layer and located in the passivation layer between the source and the gate electrodes. The simulated results of the proposed device exhibit high breakdown voltage (BV) and low specific on-resistance (RonA).The BV can reach 2453 V and the RonA reach 2.23 mΩ·cm2.Compared with the conventional GaN SJ CAVET, the improvement of RonA and BV can realized in DL-SJ CAVET based on the special structure features. To improve the RonA, we proposed a novel DL-SJ CAVET with step-doping p-pillars and n-pillars (DS-SJ CAVET). Compared with DL-SJ CAVET under the same aspect ratio, DS-SJ CAVET can further decrease RonA by increasing differently doped layers in p-pillars and n-pillars. The RonA reaches 1.76 mΩ·cm2 while BV reaches 2640 V. Further reduction in RonA can be achieved by adding differently doped layers and differently doped concentrations in n-pillars and p-pillars with decreasing BV. The proposed devices can be fabricated by selective area growth (SAG) technology and it shows significant potential in microwave power applications.

Past studies have demonstrated the positive impact of step-graded $p$ -type AlxGa1−xN/GaN superlattice (SL) electron blocking layer (EBL) structures on the efficiency performance of ultraviolet (UV) GaN-based light-emitting diodes (LEDs). However, the optimal Al-grading structure of these SL EBLs remains unclear owing to a lack of systematic investigation. The present work addresses this issue by applying EBL composed of alternating half-peak, single-peak, and double-peak $p$ -type AlxGa1−xN/GaN SL structures with varying values of $x$ ranging from 0.05 to 0.15 in 0.05 step increments. Simulation analysis is employed to obtain the internal quantum efficiency (IQE), energy band diagrams, polarization compensation factor, hole concentration, and electron concentration of GaN-based UV LEDs with three different SL-EBL structures. The results obtained at an injection current of 200 mA demonstrate that UV LEDs with double-peak SL-EBL structures provide the maximum IQE, which is ~38% greater than that of devices employing the conventional EBL in simulation experiment. This SL-EBL is demonstrated to improve the hole injection and electron overflow performance of GaN-based UV LEDs owing to the polarization charge and lattice mismatch at the p-AlxGa1−xN/GaN interfaces. The reduced Al composition on the p-GaN side reduces the potential barrier of hole injection. Moreover, the predicted increase in the IQE of GaN-based UV LEDs with the optimal SL-EBL is verified experimentally.

A GaN-based vertical superjunction high electron mobility transistor (SJ HEMT) with a composite structure (CS-SJ HEMT) is proposed and analyzed by Silvaco TCAD to improve the breakdown voltage and specific on-resistance (RonA). In this paper, CS-SJ HEMT is compared with SJ HEMT with traditional structure (TS-SJ HEMT), SJ HEMT with only particular doping pillars (DP-SJ HEMT) and SJ HEMT with only special P-gate (SP-SJ HEMT). The particular doping pillars mean the doping concentration of n-pillar increases with a gradient from top to bottom, and the concentration of p-pillar is the same as the middle of n-pillar, which reduces the RonA by only 4%. The special P-GaN cap layer can reduce the RonA by 10%, and it can even increase the on-state current in the saturation region. The CS-SJ HEMT combines both doping pillars and special P-gate structures, and the RonA can be reduced by 14%. By the optimized design, the RonA can be reduced by 30% with BV = 2580 V, or the RonA can be reduced by 21% with BV = 2720 V. These results show that the composite structure of SJ HEMT contributes to improving the BV and RonA and propose a useful approach for improving the vertical HEMTs.

Past studies have demonstrated the positive impact of step-graded $p$ -type Al x Ga1− x N/GaN superlattice (SL) electron blocking layer (EBL) structures on the efficiency performance of ultraviolet (UV) GaN-based light-emitting diodes (LEDs). However, the optimal Al-grading structure of these SL EBLs remains unclear owing to a lack of systematic investigation. The present work addresses this issue by applying EBL composed of alternating half-peak, single-peak, and double-peak $p$ -type Al x Ga1− x N/GaN SL structures with varying values of $x$ ranging from 0.05 to 0.15 in 0.05 step increments. Simulation analysis is employed to obtain the internal quantum efficiency (IQE), energy band diagrams, polarization compensation factor, hole concentration, and electron concentration of GaN-based UV LEDs with three different SL-EBL structures. The results obtained at an injection current of 200 mA demonstrate that UV LEDs with double-peak SL-EBL structures provide the maximum IQE, which is ~38% greater than that of devices employing the conventional EBL in simulation experiment. This SL-EBL is demonstrated to improve the hole injection and electron overflow performance of GaN-based UV LEDs owing to the polarization charge and lattice mismatch at the p- Al x Ga1− x N/GaN interfaces. The reduced Al composition on the p- GaN side reduces the potential barrier of hole injection. Moreover, the predicted increase in the IQE of GaN-based UV LEDs with the optimal SL-EBL is verified experimentally.

The advent of mini-light-emitting diodes (mini-LEDs) represents a recent advancement in display technology. The biggest advantage of mini-LEDs over traditional backlight LED panels is that the LED array facilitates the local dimming of light intensity. This paper presents a large-view-angle (LVA) GaN-based mini-LED chip with batwing angular light distribution. By placing a translucent layer on the mini-LED, the angular light-intensity distribution can be modified from the Lambertian type to that resembling a batwing using translucent sublayer pairs. Compared to conventional mini-LEDs, the proposed mini-LED chip requires fewer LEDs and a shorter light-diffusing distance to maintain good uniformity without additional lens packaging. Further, the increased sublayer pair count in the translucent layer affords an increase in the radiation half-power angle from 137.5° to 173.2°. This increases the half-power angle of the mini-LED array from 47.4% to 89.1%. The findings of this study demonstrate significant potential for use in the development of ultrathin backlight panels, which are finding commercial utility in modern television designs. This work should provide the applications solution in mini-LED backlit and wide color gamut RGB backlight display.

Light-emitting diodes (LEDs) with high response frequency and high power can be applied in visible light communication (VLC). This letter studies the response frequency and optical output power of the gallium nitride (GaN) based matrix micro-LED ( $\mu $ LED) for visible light communication. The blue-emitting GaN $\mu $ LEDs with the format from ${1}\times {1}$ to ${6}\times {6}$ are fabricated and used to analyze the relationship between the matrix format and the response frequency, as well as the output optical power and the data transmission performance of the matrix $\mu $ LED. The experimental and analysis results show that the GaN-based matrix $\mu $ LED response frequency can be improved by an increase in the injection current density increased and a decrease in device capacitance. The experimental comparison result indicates that the −3 dB response frequency changed from 85 MHz to 401 MHz at a 60 mA injection current progressively increased as the matrix array size from ${1}\times {1}$ to ${6}\times {6}$ , the ${6}\times {6}$ matrix $\mu $ LED optical output power reaches a value of 356.7 mW.

We analysis the RF performance of novel Sc-Doped GaN high-electron-mobility transistors (HEMTs) with asymmetric air-bridge structure by TCAD software. The maximum oscillating frequency (fMAX) which has been achieved in this work is 41.2 GHz and the cutoff frequency (fT) reached 30.2 GHz, while the HEMT with conventional structure attained to only 12.9 GHz and 9 GHz respectively. This work has been performed on novel p-GaN HEMT device. The air-bridge is designed to be asymmetrical in width and the ScAlN layer is innovatively placed between the AlGaN and GaN layers as part of the heterojunction. It is found that the thickness change of scandium layer will bring great influence on a higher transconductance (from 9.22 × 10−3 S/mm to 3.187 × 10−2 S/mm), lower electron concentration (from 5.01 × 1019/cm3 to 3.16 × 1018/cm3) and higher electron velocity (from 5.52 × 107cm/s to 2.30 × 108cm/s) of the device. In addition, the combined influence of air bridge and scandium layer structure on the capacitance and other parameters were analyzed, which propose a useful approach for improving the DC and RF characteristic of GaN HEMTs.

In this paper, we numerically investigated the emission characteristics of surface plasmon (SP)-enhanced deep ultraviolet light emitting diode (DUV-LED) by employing Al/Al2O3 core-shell nanoparticle(NP) structure on the p-GaN contact layer by utilizing finite-difference time-domain (FDTD) method. The results suggest that normalized dipole power of TE (TM) polarization is enhanced (inhibited) in the DUV range by coupling with in-plane substrate localized surface plasmon (LSP) mode from Al/Al2O3 core-shell nanoparticle (NP). It is found that normalized upward extraction power for both polarizations can also be significantly increased by scattering effect when photons and excitons coupling with in-plane air LSP mode induced on the NP; thus, the light extraction efficiency (LEE) can be substantially enhanced. The depth d between quantum well (QW) and NP and NP size have a remarkable influence on LSP resonance wavelength. Through careful regulation of NP size and depth d, the emission characteristics in DUV range (240–280 nm) exhibit a considerable amelioration.

Based on the research of surface plasmon (SP) applied to Vertical-Cavity Surface-Emitting Lasers (VCSEL), we proposed a new 465 nm GaN-based VCSEL to enhance illumination by deposit Al rectangular grating onto p-i-n layer. Meanwhile, an increase in the effective radiated power was obtained by the control of a surface plasmon mode, which depends strongly on the structural parameters such as material, period, depth and dipole location. Compared to conventional structure, we have a 30% improvement in effective radiated power. Such advantages make surface Al-grating be an alternative low-cost and simple technique used in SP-coupled VCSEL for the blue range.

We theoretically investigate the effects of three independent p-type contact layers on the photoelectric properties of deep ultraviolet light-emitting diodes (DUV-LEDs). From the simulation results, the DUV-LED using a w-shaped p-AlGaN layer has a better photoelectric performance. The internal quantum efficiency and output power in the new structure are significantly increased compared to the two other structures. Besides, the novel structure reveals lower contact resistance and higher electroluminescence intensity, and the efficiency droop is very small at 200 mA injection current. These improvements are attributed to not only decreased electron leakage but also increased hole injection efficiency, thereby enhancing radiative recombination rates. The specially designed p-type layer provides an attractive solution for improving the photoelectric performance of DUV-LEDs with the Al-rich p-AlGaN contact layers.

The localized surface plasmon enhanced luminescence behaviors of a radiating dipole in an all-inorganic perovskite light-emitting diode (PeLED) by incorporating a gold (Au)-silver (Ag) alloy nanoparticle (NP) in the electronic transport layer are demonstrated. The analyses of finite difference time domain (FDTD) show that the localized surface plasmon resonance (LSPR) wavelength mainly depends on the size and the material composition of NP. An increase of 25% of the luminescence efficiency can be achieved by selecting the proper size and the Au molar fraction of the alloy NP. This result can be attributed to the match between the LSPR wavelength of NP and emission peak of PeLED. And the luminous performance of PeLED can be improved by optimizing the thickness of functional layers. This finding indicates great potential of Au-Ag alloy nanoparticle in developing the efficiency of PeLEDs and provides a new method for the future improvement of PeLEDs.

As an economically important crop, tea is widely cultivated in more than 50 countries and has numerous health benefits. Metabolomics has considerable advantages in the analysis of small molecules and has been widely used in tea science. We applied a metabolomic method to evaluate the dynamic changes in metabolites and pathways in the large-, middle- and small-leaf cultivars of Camellia sinensis (L.) Kuntze var. niaowangensis grown in the same area from Yunwu Mountain. The results indicate that flavonoid biosynthesis, stilbenoid, diarylheptanoid and gingerol biosynthesis, citrate cycle (TCA cycle), and propanoate metabolism may play important roles in the differences among cultivars. The levels of tea polyphenols, flavonoids and amino acids may impact the sensory properties of teas of different cultivars. Our results may help to elucidate the mechanism underlying the difference in tea quality and offer references for the breeding of high-quality tea cultivars.

Improve the light extraction efficiency and light output in the vertical direction of LEDs for high-power applications, flip-chip LEDs (FCLEDs) with an Ag/SiO2/distributed Bragg reflector/SiO2 composite reflection structure (CRS) were fabricated. The enhanced opto-electrical properties were thoroughly investigated. Compared with the normal Ag-based FCLEDs, the light output power of the CRS-FCLEDs is increased by 6.3% at an operational current of 1500 mA, with the corresponding external quantum efficiency improved by 6.0%. Further investigation proved that the CRS structure exhibited higher reflectance compared with the commonly used Ag-mirror reflective structure, which originates from the increased reflective area in the sidewall and partial area of the n-GaN contact holes. Moreover, the light emission intensity distributions and far-field angular light emission measurements show that the CRS-FCLED has a strengthened light output in the vertical direction, which shows great potential for applications in high-power fields, such as headlamps for automobiles.

Transcriptome profiles have been widely captured using short-read sequencing technology, but there are still limitations partially due to the read length. Here, we generated long reads using Oxford Nanopore PromethION™ technology and short reads using the Illumina sequencing platform to study the transcriptome of root, stem, and leaf of Camellia sinensis cv. Fudingdabai. We mapped the Nanopore reads to the Shuchazao of C. sinensis genome sequence, and the mapping rates ranged from 82.63% to 90.59% (average 86.44%); this is lower than that of the Illumina reads which was 87.83% to 91.14% (average 90.12%). Gene expression level was quantified using the Nanopore and Illumina data and we observed a good agreement. The same tea leaf flavor synthesis pathways were highlighted using both sequencing technologies when analyzing the differentially expressed genes between leaf and root. Alternative splicing was then analyzed, and the intron-retention was observed as the most common alternative splicing. Moreover Nanopore long reads could correct transcript isoform annotation for differential expression investigation purposes. Nanopore sequencing techniques can provide a novel reference basis for molecular analysis of tea plants.

The AlGaN-based deep ultraviolet light emitting diodes (DUV-LEDs) with a graded superlattice hole reservoir layer (HRL) can significantly enhance hole injection efficiency, compared with the traditional LED. We have systematically studied by APSYS software. The application of new structure can obtain higher output power and carrier concentrations, and further influence the carrier recombination rate. The DUV-LEDs with a graded superlattice HRL can obviously improve internal quantum efficiency (IQE) and alleviate efficiency droop. The improved performance is mainly attributed to the higher electron potential height and lower hole potential height, so it enhances electron confinement and hole injection. Thereby, the proposed structure effectively improve the photoelectric performance.

The characteristics of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) with electroluminescence peak wavelength of emission about 289 nm have been investigated by optimizing the last quantum barrier (LQB) in the active region. The results demonstrate that the internal quantum efficiency and radiative recombination rate of DUV-LEDs with a graded superlattice last quantum barrier (GSL LQB) and without an electron blocking layer (EBL) are higher than for other structures under current of 180 mA. Also, the electron and hole leakage currents are reduced for the GSL LQB structure. This structure contributes to effective electron confinement and hole injection owing to increased overlap of electron and hole wavefunctions resulting from low electrostatic fields in the active region. As a result, the optical output power of the structure with a GSL LQB and without an EBL is increased by 1.62 times, and the spontaneous emission intensity by 1.56 times, compared with the conventional structure.

In order to improve the electrical and optical performance of ultraviolet light emitting diodes (UV-LEDs), Al0.65Ga0.35N/AlxGa1-xN graded superlattice hole blocking layers (GS-HBLs) and Al0.65Ga0.35N/AlxGa1-xN graded superlattice electron blocking layers (GS-EBLs) are applied to the traditional AlGaN-based UV-LEDs. Compared to conventional structure, our new structure can obtain much higher internal quantum efficiency (IQE), output power and lower efficiency droop. In order to reveal the underlying physical mechanism of this unique structure, we have studied it numerically by the Advance Physical Model of Semiconductor Devices (APSYS) simulator. We find that GS-EBLs can obviously increase the electron potential height and reduce the hole potential height, produce less electron leakage and more hole injection, leading to higher carriers concentration. GS-HBLs can obviously reduce the hole leakage, reduce the thermal velocity and correspondingly the mean free path of the hot electrons, and increase the electron injection. This enhanced the electron capture efficiency of the multiple quantum wells, which can also help to reduce electron leakage and improve recombination rate and IQE.

The AlGaN-based deep ultraviolet light-emitting diodes with an Mg-Si pin-doped AlGaN layer inserted, between the active region and electron-blocking layer, have been systematically investigated by APSYS software. The energy band diagram, carrier distribution, and radiative recombination are studied. When compared with the conventional deep ultraviolet light-emitting diodes, the simulation results demonstrate that the proposed structure has effectively improved the output power, internal quantum efficiency, carrier concentrations, and radiative recombination rate. Based on the analysis of electrical and optical properties, and the performance improvements provided by using a pin-doped layer, we conclude that they are mainly attributed to the suppression of quantum-confined Stark effect as well as electron confinement and hole-injection enhancement in the active region effectively. In addition, the optimized thickness of this insert layer has been achieved after detailed research. As a result, the AlGaN-based deep ultraviolet light-emitting diodes with 10-nm-thick insert layer demonstrate improved performance.

The optical and electrical properties of AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) with the novel Mg-doping hole strengthened-injection layer (HSIL) are studied numerically and ...

Ultraviolet light-emitting diodes (UVLEDs) with staggered barriers have been studied. The energy band diagrams, internal quantum efficiency, total output power and radiative recombination rate are investigated by APSYS software. The simulation results show that the UVLED with staggered barriers get a little enhancement comparing to the conventional one, on the contrary the structure with p-doped staggered barriers has higher efficiency and power due to enhancement of the holes' injection and the electrons' confinement. Then structures with different Al content in the Mg-doped barriers have been studied numerically and that confirmed the best.

The effect of using inverted-Y-shaped barriers with alternate doped Si and Mg in traditional AlGaN-based ultraviolet light-emitting diodes (UV-LEDs) has been investigated through APSYS simulation program. The results indicated that the specially designed UV-LED has better light output power and internal quantum efficiency (IQE) compared with the conventional AlGaN barriers and the AlGaN composition-graded barriers. Efficiency droop of the new structure reduced to 2.17% while 41.73% in conventional LED. In addition, alternating doped Si and Mg in AlGaN composition-graded barriers obviously improves the hole injection efficiency, modulate carrier distribution and suppress electron spill out from active region, and thus enhances the carrier radiation recombination rate, ameliorate IQE and optical output power.

Emission enhancement of a radiating dipole at a desired emission wavelength in blue range coupling with a surface plasmon (SP) resonance mode induced on a nearby surface Al nanoparticle (NP) is demonstrated. Meanwhile, increasing the size of the NP and utilizing a high refractive index dielectric layer to cover the NP are effective approaches to a spectral red-shift of the SP resonance mode of Al, the location and direction of the radiating dipole also play important roles in the SP coupling effect. Such advantages make surface Al NP be an alternative low-cost and simple technique used in SP-coupled light-emitting diodes.

Al x Ga 1-x N/Al 0.6 Ga 0.4 N graded superlattice hole blocking layers (GSL-HBLs) and Al x Ga 1-x N/Al 0.6 Ga 0.4 N graded superlattice electron blocking layers (GSL-EBLs) are applied to the traditional AlGaN-based ultraviolet light-emitting diodes (UVLEDs). This can obtain much higher internal quantum efficiency (IQE) and output power. In order to reveal the underlying physical mechanism of this unique structure, we have studied it numerically by APSYS simulation programs. We find that GSL-EBLs can obviously increase the electron potential height and reduce the hole potential height, produce less electron leakage and more hole injection, leading to higher carrier contration. GSL-HBLs can obviously reduce the hole leakage, reduce the thermal velocity and correspondingly the mean free path of the hot electrons, and increase the electron injection. This enhanced the electron capture efficiency of the multiple quantum wells, which can also help to reduce electron leakage.

The AlGaN-based deep ultraviolet light-emitting diodes with a p-type Al0.92In0.08N/Al0.55Ga0.45N superlattice electron-blocking layer are studied numerically. The energy band diagrams, radiative recombination rate, electron leakage current, light output power and internal quantum efficiency are investigated. The simulation results show the structure has a low electron leakage current and high hole injection efficiency compared to the original deep ultraviolet light-emitting diodes, which is ascribed to the deep ultraviolet light-emitting diodes with a p-type Al0.92In0.08N/Al0.55Ga0.45N superlattice electron-blocking layer having a low polarization effect on the interface between the last quantum barrier and the electron-blocking layer. As a result, the radiative recombination rate and the light output power are significantly enhanced.

The taxonomic problem of cryptic species has long been recognized. Hemiboea subcapitata C. B. Clarke is a widespread and morphologically diverse species including two varieties, H. subcapitata var. subcapitata C. B. Clarke and H. subcapitata var. guangdongensis (Z. Y. Li) Z. Y. Li. However, genetic distance and molecular phylogenetic analyses based on nuclear ITS and four plastid DNA sequences (atpB‐rbcL, matK, rbcL, rpS16 intron) revealed that H. subcapitata var. guangdongensis is sister to H. subacaulis, and separated from H. subcapitata var. subcapitata, suggesting that it should be raised to the rank of an independent species as H. guangdongensis (Z. Y. Li) X. Q. Li & X. G. Xiang, comb. & stat. nov. Morphologically, the new species can be distinguished from H. subacaulis by its calyx 5‐sect from base, segments narrowly oblong‐lanceolate (versus calyx 5‐sect from base or 2‐lipped and adaxial lip 2‐lobed from below middle, segments ovate), peduncle glabrous (versus pubescent), and vermiform sclereids dispersed in leaf mesophyll (versus without sclereids).

Strong light decreases the rate of photosynthesis and assimilates production of crop plants. Plants with different carbon reduction cycles respond differently to strong light stress. However, variation in photoinhibition in leaves with different photosynthetic characteristics in maize is not clear. In this experiment, we used the first leaves (with an incomplete C4 cycle) and fifth leaves (with a complete C4 cycle) of maize plants as well as the fifth leaves (C3 cycle) of tobacco plants as a reference to measure the photosynthetic rate (PN) and chlorophyll a parameters under strong light stress. During treatment, PN, the maximal fluorescence (Fm), the maximal quantum yield of PSII photochemistry (Fv/Fm), and the number of active photosystem II (PSII) reaction centers per excited cross-section (RC/CSm) declined dramatically in all three types of leaves but to different degrees. PN, Fm, Fv/Fm, and RC/CSm were less inhibited by strong light in C4 leaves. The results showed that maize C4 leaves with higher rates of photosynthesis are more tolerant to strong light stress than incomplete C4 leaves, and the carbon reduction cycle is more important to photoprotection in C4 leaves, while state transition is critical in incomplete C4 leaves.

The application of a p-type superlattice hole reservoir layer in the traditional ultraviolet light-emitting diodes (UVLED) can obtain better Internal quantum efficiency (IQE) and output power, ease the problem about efficient carrier movement in high Al-content AlGaN material. Through computation and analysis by using the APSYS simulation software, the change of position of the hole reservoir layer can influence the luminous efficiency. The design of a superlattice hole reservoir layer between electron blocking layer (EBL) and p-type AlGaN layer can obviously reduce the hole potential height and increase the electron potential height, produce more hole injection and less electron leak, leading to higher carrier concentration, so as to realize the further increased for carrier recombination rate.

Ultra violet light-emitting diodes (UVLEDs) with different types of Mg-doped barriers have been studied. The energy band diagrams, internal quantum efficiency, total output power and radiative recombination rate are investigated by APSYS software. The simulation results show that the UVLED with only a p-doped top barrier get little enhancement comparing to the conventional one, on the contrary the structure with p-doping in all but the bottom barriers has a much better optical and electrical properties due to enhancement of the holes’ injection and the electrons’ confinement. The efficiency droop is significantly alleviated and the light output power is greatly enhanced. To avoid forming a PN junction by the bottom barrier and the n-AlGaN in the proposed structure, therefore, the bottom barrier isn’t p-doped. Then structures with different hole densities in the Mg-doped barriers have been studied numerically and that confirmed the best.

Optical performances of blue InGaN light-emitting diodes (LEDs) with an undoped AlGaN electron-blocking layer (U-AlGaN EBL) embedded in the active region are investigated numerically. As a benefit of this special structural design, the electrons would spill over the EBL and recombine with the holes in the wells close to the p-side. Moreover, holes in the wells that are close to the n-side increase to a higher concentration due to the presence of a new shallow potential well in the valence band. The simulation results indicate that the LEDs with U-AlGaN EBL has higher internal quantum efficiency as well as light output power compared with the conventional single p-type AlGaN EBL structure. These improvements are primarily contributed to the enhancement on electrons confinement and holes injection.

TiO2 nanoballs modified with Pt nano particles (Ptnp/TiO2-NB) were first applied with a Cu2ZnSnS4-based photocathode for solar water splitting. It was found that the loaded amount of Ptnp and the thickness of the Ptnp/TiO2-NB layer significantly impact the photoelectrochemical (PEC) properties of the Cu2ZnSnS4-based photocathode. Compared with the TiO2 layer achieved by atomic layer deposition (ALD), the nanoball-structured TiO2 exhibits many superiorities, such as a high specific surface area with significant hydrophilia, low preparation cost and controllable size. Ptnps were observed to be easily and homogeneously dispersed on the outer surface of TiO2-NBs. This combination not only greatly increased the number of active points and enhanced the solar water splitting efficiency but also induced the Pt catalyst points to be uniformly located on the 3D-structured TiO2 layer of the resultant photoelectrode. In addition, the hydrophilicity of TiO2-NB and Ptnp's adsorption of H+ ions allow the surface area of the 3D layer composed of Ptnp/TiO2-NB spheres to be fully utilized for hydrogen production. Interestingly, the surface SPR effect exists at the Ptnp/TiO2-NB layer and can influence the charge transfer efficiency at the photocathode/solution interface. Furthermore, the SPR-induced enhanced electrical field also affected the inner potential of the Ptnp/TiO2-NB/CdS/CZTS photocathode and therefore impacted the carrier transfer within the photocathode. As a result, the best VOC of 0.7 VRHE, a J0 of 17.2 mA/cm2 and the highest HC-STH efficiency of over 3.5% were achieved by the Ptnp/TiO2-NB/CdS/CZTS photocathode.

In quantum networks, photons are used as flying qubits. The solid-state single quantum emitter based on the Diamond NV (Nitrogen-Vacancy) center exhibits good single-photon emission characteristics, which is the basis of a series of quantum technologies. Due to the high refractive index of the diamond, refraction and reflection at the material interface will hinder the collection of photons. Therefore, we designed a metalens formed by nano-scale rutile TiO2 pillar elements as an immersion lens to improve the collection efficiency of the deep diamond NV center at 700 nm, it is emphasized that the metalens is a technology that achieves light focusing beyond the diffraction limit through the surface micro-nano structure. This kind of structural design will be conducive to miniaturization of quantum devices and the development of single-photon-emitting metasurface based on fiber coupling.

Use of dipole-like localized surface plasmons (LSPs) induced on a rectangular array of silver nanodisks to excite directional surface plasmon polaritons (SPPs) on a flat silver film is demonstrated. By modifying the spectral resonance of the LSPs, an effective coupling of the incident light into the SPPs has been achieved at operational wavelength of λ0 = 628 nm. The maximum SPP intensity exceeds 25% of the incident intensity. Meanwhile, owing to the angle-dependent spatial distribution of the LSPs and the constructive interference between columns or rows of the array, the excited SPPs are supported to propagate in two orthogonal channels with a width of 1756 nm. Moreover, the propagation of the SPPs is tunable by rotating the polarization direction of the incident light between angles of 0 and π/2. This approach of launching direction-tunable SPPs shows great potential in applications of integrated plasmonic circuits.