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A shallow acceptor level is formed for the thermally stable β-Ga2O3:NO(II)–VGa(I) complexes due to the Coulomb binding between NO(II) and VGa(I).

A defense and further discussions are provided for the paper [Phys. Chem. Chem. Phys., 2022, 24, 5529–5538]. The dominant effects of orbital coupling and Coulomb interaction on the Mg-doped AlN/AlGaN QWs are emphasized in the reply.

The emerging semiconductor spintronics has offered a practical routine for developing high-speed and energy-efficient electronic and optoelectronic devices. GaN holds broad prospects for room-temperature spintronic applications due to its weak spin scattering and moderate spin–orbit coupling. However, the development of GaN-based spintronic devices is still hindered by the relatively low spin injection efficiency and gate controllability. In this study, gate-modulated spin transport was achieved in a highly spin-polarized GaN-based non-local spin valve. A maximum spin diffusion length of 510 nm and a high spin polarization of 14.1% was obtained with the CoFeB/MgO tunnel spin injector. By applying gate voltages from −3 to +3 V, the spin-dependent magnetoresistance can be tuned in the range of 1.6–3.9 Ω. The modulation is attributed to the controllable spin relaxation of electrons by the gate electric field. This work has demonstrated high spin polarization and exceptional electric controllability in GaN, pushing forward the research in spin field-effect transistors.

Hydrogen, the smallest element, easily forms bonds to host/dopant atoms in semiconductors, which strongly passivates the original electronic characteristics and deteriorates the final reliability. Here, we demonstrate a concept of unidirectional elimination of hydrogen from semiconductor wafers as well as electronic chips through a giant local electric field induced by compact chloridions. We reveal an interactive behavior of chloridions, which can rapidly approach and take hydrogen atoms away from the device surface. A universal and simple technique based on a solution-mediated three-electrode system achieves efficient hydrogen elimination from various semiconductor wafers (p-GaN, p-AlGaN, SiC, and AlInP) and also complete light emitting diodes (LEDs). The p-type conductivity and light output efficiency of H-eliminated UVC LEDs have been significantly enhanced, and the lifetime is almost doubled. Moreover, we confirm that under a one-second irradiation of UVC LEDs, bacteria and COVID-19 coronavirus can be completely killed (99.93%). This technology will accelerate the further development of the semiconductor-based electronic industry.

Quantum states and arrangement of valence levels determine most of the electronic and optical properties of semiconductors. Since the crystal field split-off hole (CH) band is the top valence band in high-Al-content AlGaN, TM-polarized optical anisotropy has become the limiting factor for efficient deep-ultraviolet (DUV) light emission. Additional potentials, including on-site Coulomb interaction and orbital state coupling induced by magnesium (Mg) doping, are proposed in this work to regulate the valence level arrangement of AlN/Al

The feasibility and conductivity mechanisms of p-type N-doped β-Ga2O3 are demonstrated and clarified using first-principles hybrid functional calculations and the phase transition technique.

This study presents broadband ultraviolet photodetectors (BUV PDs) based on Ga2O3/GaN core-shell micro-nanorod arrays with excellent performance. Micro-Nanoarchitectonics of Ga2O3/GaN core-shell rod arrays were fabricated with high-temperature oxidization of GaN micro-nanorod arrays. The PD based on the microrod arrays exhibited an ultrahigh responsivity of 2300 A/W for 280 nm at 7 V, the peak responsivity was approximately 400 times larger than those of the PD based on the planar Ga2O3/GaN film. The responsivity was over 1500 A/W for the 270–360 nm band at 7 V. The external quantum efficiency was up to 1.02 × 106% for 280 nm. Moreover, the responsivity was further increased to 2.65 × 104 A/W for 365 nm and over 1.5 × 104 A/W for 270–360 nm using the nanorod arrays. The physical mechanism may have been attributed to the large surface area of the micro-nanorods coupled with the Ga2O3/GaN heterostructure, which excited more photogenerated holes to be blocked at the Ga2O3 surface and Ga2O3/GaN interface, resulting in a larger internal gain. The overall high performance coupled with large-scale production makes it a promising candidate for practical BUV PD.

The controlled growth of single-crystalline (InxGa1-x)2O3-based materials with high indium contents is still a big challenge due to the large solid-phase miscibility gap, unclear growth mechanism, and the lack of...

We report a remarkably enhanced responsivity of metal–semiconductor–metal photodetectors embedded with a large-scale periodicity and highly uniform rhodium nanoparticle array based on localized surface plasmon resonance.

The doping of ZnO has attracted lots of attention because it is an important way to tune the properties of ZnO. Post-doping after growth is one of the efficient strategies. Here, we report a unique approach to successfully dope the single crystalline ZnO with Ag by the laser-induced method, which can effectively further post-treat grown samples. Magnetron sputtering was used to coat the Ag film with a thickness of about 50 nm on the single crystalline ZnO. Neodymium-doped yttrium aluminum garnet (Nd: YAG) laser was chosen to irradiate the Ag-capped ZnO samples, followed by annealing at 700℃ for two hours to form ZnO:Ag. The 3D information of the elemental distribution of Ag in ZnO was obtained through time-of-flight secondary ion mass spectrometry (TOF-SIMS). TOF-SIMS and core-level X-ray photoelectron spectroscopy (XPS) demonstrated that the Ag impurities could be effectively doped into single crystalline ZnO samples as deep as several hundred nanometers. Obvious broadening of core level XPS profiles of Ag from the surface to depths of hundred nms was observed, indicating the variance of chemical state changes in laser-induced Ag-doped ZnO. Interesting features of electronic mixing states were detected in the valence band XPS of ZnO: Ag, suggesting the strong coupling or interaction of Ag and ZnO in the sample rather than their simple mixture. The Ag-doped ZnO also showed a narrower bandgap and a decrease in thermal diffusion coefficient compared to the pure ZnO, which would be beneficial to thermoelectric performance.

Structure has been considered to play an important role in photocatalytic performance of the semiconductors, but the intrinsic factors were rarely revealed. Herein, ZnO nanomaterials in the structures of thin film, nanowire array and nanosheet array were synthesized, and their structural characteristics, optical properties, photocurrent response and photocatalytic efficiency were compared with each other for illustrating the issue. The photoluminescence intensity decreased in the order of nanosheets, thin film and nanowires for improved lifetime of the photoexcited charges. The absorption of the nanosheets and nanowires improved obviously in the visible range with a redshift of the absorption edge than that of the thin film. The nanowires possessed the highest response current of 82.65 μA at a response time of 2.0 ms in a sensitivity of 87.93 at the light frequency of 1 Hz, and gained the largest catalytic efficiency of 2.45 μg/cm2 h for the methylene blue degradation in UV light. Nevertheless, the improvement of catalytic efficiency of the nanosheets (up to 42.4%) was much larger than that of nanowires (5.7%) and thin film (2.6%) for the Au coating. The analysis revealed that the photocatalytic efficiency of the ZnO nanomaterials was modulated by the structure as it contained different surface area, roughness, defect and doping states, vacancies, polar and non-polar crystalline faces, which would provide structural design of semiconductor nanomaterials for the photoelectric and photocatalytic applications.

Valleytronics in transition metal dichalcogenides has been intensively investigated for potential applications in next-generation information storage, data processing, and signal transmission devices. Here a ferroelectric gating approach is engaged in achieving nonvolatile electrical tuning of the valley-excitonic properties of monolayer and bilayer WS

Localized surface plasmons exhibit promising capabilities in optoelectronic devices. In most cases, the metal nanoparticle arrays are located on interfaces or inside optical cavities. Fano interferences have been observed and explained via the interference between the waves generated by the localized surface plasmon and dielectric interfaces. Conventionally, these Fano interferences are modeled using the modified Fresnel equation. However, certain issues persist in the fundamental physics or in the numerical calculation process. Here, we adopt the equivalent medium theory (Maxwell-Garnett theory, MGT) to calculate and elucidate Fano interferences in different structures, in the region comprising nanoparticle arrays and dielectrics equivalent to a homogeneous layer of media via the mean field theory. Using this method, the Fano interference can be modeled by mixing different materials, i.e., metals and dielectrics in these cases. Furthermore, a multiple-layered equivalent medium theory is proposed to significantly improve the scalability of this simplified numerical method. In other words, this method can be easily extended to nanoparticles with different shapes, sizes, and materials; in addition, it exhibits robust practicability. Compared with the modified Fresnel equation and finite-difference time-domain methods, this MGT-based method can effectively minimize the calculation process, which is beneficial to the prospective application of plasmon photonics.

Transition-metal dichalcogenides with intrinsic spin-valley degree of freedom have enabled great potentials for valleytronic and optoelectronic applications. However, the degree of valley polarization is usually low under nonresonant excitation at room temperature due to the phonon-assisted intervalley scattering. Here, achiral and chiral Au arrays are designed to enhance the optical response and valley polarization in monolayer and bilayer WS2. A considerable band edge emission with 7 times increment is realized under the resonant coupling with Au dimer-prism arrays. Valley polarization enhancement is quantitatively predicted by the inherent mechanisms from elevated electromagnetic field intensity and radiation efficiency and further realized in polarized photoluminescence. A tunable valley polarization up to 30.0% is achieved in bilayer WS2 under a nonresonant excitation at room temperature. All of these results provide a promising route toward the development of room-temperature valley-dependent optoelectronic devices.

Plasmonic coupling has been demonstrated to be an effective manipulation strategy for emission enhancement in low-dimensional semiconductor materials. Here, dual-mode plasmonic resonances based on a metal dimer structure were proposed to simultaneously enhance the absorption under short-wavelength excitation and excitons' emission at longer wavelengths for CsPbBr3 perovskite quantum dots (QDs). Large-area metal nanodimer arrays with well-controlled local surface plasmon resonance were facilely fabricated by a simple method combined with metal angular deposition and nanosphere lithography. With the addition of an optimized polymethyl methacrylate spacer, the effective plasmonic coupling and interfacial passivation of QDs were successfully achieved in the hybrid system. As a result, the QD films exhibited a significant and approximately 3.95-fold overall fluorescence enhancement when using blue light excitation, showing the novel advantages of dual-mode plasmonic coupling of semiconductor quantum structures for color conversion applications.

Memristors with non-volatile storage performance and simulated synaptic functions are regarded as one of the critical devices to overcome the bottleneck in traditional von Neumann computer architecture. van der Waals heterostructures integrating excellent properties of two-dimensional semiconductor materials, possessing controllable optoelectronic properties and high compatibility with conventional microelectronic technology, have paved a new way for the development of advanced memristors. Herein, we demonstrate a two-dimensional planar memristor with both electrical and optical controllability based on ReS2/WS2 van der Waals heterostructure. The device shows a typical unipolar non-volatile behavior with a high Ron/Roff ratio, multiple tunable resistance states, and desirable endurance and retention. It also successfully realizes biological synaptic functions and plasticity, including spike rate-dependent plasticity and paired-pulse facilitation. Furthermore, the developed device shows a significant gate controllability and a remarkable optical tunability. The superior performance is attributed to the unique optoelectronic property and the interlayer interaction in the heterostructure. The research presented here demonstrates the potential of two-dimensional van der Waals heterostructures for high-performance memristor applications and further developments in modelling biological synapses.

As demonstrated during the COVID-19 pandemic, advanced deep ultraviolet (DUV) light sources (200–280 nm), such as AlGaN-based light-emitting diodes (LEDs) show excellence in preventing virus transmission, which further reveals their wide applications from biological, environmental, industrial to medical. However, the relatively low external quantum efficiencies (mostly lower than 10%) strongly restrict their wider or even potential applications, which have been known related to the intrinsic properties of high Al-content AlGaN semiconductor materials and especially their quantum structures. Here, we review recent progress in the development of novel concepts and techniques in AlGaN-based LEDs and summarize the multiple physical fields as a toolkit for effectively controlling and tailoring the crucial properties of nitride quantum structures. In addition, we describe the key challenges for further increasing the efficiency of DUV LEDs and provide an outlook for future developments., This paper review recent advances in ultraviolet LEDs and summarize that multiple physical fields could built a toolkit for effectively controlling and tailoring crucial properties of nitride quantum structures.

Semipolar III-nitrides have attracted great attention due to their weak polarization field for optoelectronic devices. High-quality AlN is a perfect template in the epitaxial growth of AlGaN-based ...

The manipulation of spin and valley degree of freedom in two-dimensional materials is desirable for emerging applications in next-generation electronics. Here, we report a regulation of the spin splitting in monolayer antiferromagnetic MnPSe3 through stacking van der Waals (vdW) heterostructures with transition-metal dichalcogenides (TMDs). Different TMDs including Janus MoSSe, MoSe2, and MoS2 are engaged and the spin and valley dependences on stacking configurations, interfacial atoms, and interlayer spacings are comprehensively investigated based on first-principles calculations. The results show that spin degeneracy of MnPSe3 can be lifted through the interfacial interaction in the vdW heterostructures. Compared with the MnPSe3 interfacing with traditional TMDs (MoSe2 and MoS2), those with Janus TMDs (MoSSe or MoSeS) have larger spin splitting. A maximal spin splitting of 50.8 meV at valence band maximum is achieved in MoSSe/MnPSe3 heterostructure, and such splitting is further enhanced to 243.0 meV when the interlayer spacing is reduced to 2.9 Å. It is found that the different hybridizations between the d-orbitals of the two inequivalent Mn atoms in MnPSe3 and the above TMDs lead to the occurrence of net magnetic moments, and thus induce spin splitting. This work paves a novel way to modify the spin-valley properties of two-dimensional semiconductors.

The AlGaN-based deep ultraviolet light-emitting diodes (DUV LEDs) dominated by transverse-magnetic (TM) polarized emission suffer from extremely poor light extraction efficiency (LEE) from their top surface, which severely limits the device performance. In this study, the underlying physics of polarization-dependent light extraction mechanisms of AlGaN-based DUV LEDs has been explored in depth via simple Monte Carlo ray-tracing simulations with Snell's law. It is especially worth noting that the structures of the p-type electron blocking layer (p-EBL) and multi-quantum wells (MQWs) have a significant impact on light extraction behavior, especially for TM-polarized emission. Thus, an artificial vertical escape channel (named GLRV) has been constructed to efficiently extract the TM-polarized light through the top surface, by adjusting the structures of the p-EBL, MQWs, sidewalls, and using the adverse total internal reflection in a positive manner. The results show that the enhancement times of the top-surface LEE is up to 18 for TM-polarized emission in the 300 × 300 µm2 chip comprising a single GLRV structure, and further increases to 25 by dividing this single GLRV structure into a 4 × 4 micro-GLRV array structure. This study provides a new perspective for understanding and modulating the extraction mechanisms of polarized light to overcome the inherently poor LEE for the TM-polarized light.

Memristors are excellent candidates for non-volatile memory and neuromorphic computing. Controlling the resistive switching polarity in certain materials holds great promise for the design and integration of multifunctional memristors. Here, bipolar and unipolar nonvolatility were realized by modulating the crystal structures, which exhibit high switching ratios, desirable cyclability, and long retention. By investigating the defect level and conductivity difference in single-crystal and polycrystal ReS2, the competition between electric field and Joule heat effects were revealed as the essential mechanism governing the switching process and memristive polarities. These results promote the design of two-dimensional memristors with controllable polarity.

The combination of zinc oxide (ZnO) and transition metal dichalcogenide (TMD) nanoparticles has higher photocatalytic efficiency and field emission performance than TMDs or ZnO, as well as significantly higher water cracking photocatalytic activity. By first-principles calculation, we investigated the structural and optoelectronic properties of the two-dimensional (2D) WS2/ZnO van der Waals (vdWs) heterostructure, and the regulation effect of biaxial strain. It is revealed that the conduction-band minimum (CBM) is lower than the reduction potential of water (EH+/H2 ≈ −4.44 eV), and the valence-band maximum (VBM) is lower than the oxidation potential (EO2/H2O ≈ −5.67 eV), thus the heterostructure is a good oxidant in the water decomposition process, but cannot match the requirements for water reduction. By applying a −2% biaxial strain, the CBM is elevated to a position higher than the reduction potential of water, then the 2D vdWs WS2/ZnO heterostructure becomes a good material for the application of water reduction and other photovoltaic and photocatalytic devices.

ZnO-based diluted magnetic semiconductors have high prospects in spintronics applications. In this study, the electronic and magnetic properties of Fe-doped MgZnO are studied by density functional theory calculations. The investigations of the band structure, total density of states, and projected density of states revealed a strong correlation between Mg and O atoms in addition to the magnetism and impurity level generated by the Fe atoms. In the spin charge density and band structure of 2.78% Fe-doped MgZnO, Fe atoms always cause paramagnetic coupling with oxygen atoms bonded around them, and when the initial magnetic moments were parallel, the band gap is broadened in the opposite channel. On the contrary, when the initial magnetic moments are anti-parallel, the band gap is narrowed in both the spin-up and spin-down channels. This shows that the initial magnetic moments have a great influence on the band structure, giving another way to tune the gap dynamically.

The ternary ZnO/MoS2/Ag2S nanorod array in a core–shell structure brings different band alignments at the interfacial heterojunctions to achieve full solar absorption with efficient charge separation and conduction and photocatalytic performance.

Asymmetric transport characteristic in n- and p-type conductivity has long been a fundamental difficulty in wide bandgap semiconductors. Hexagonal boron nitride (h-BN) can achieve p-type conduction, however, the n-type conductivity still remains unavailable. Here, we demonstrate a concept of orbital split induced level engineering through sacrificial impurity coupling and the realization of efficient n-type transport in 2D h-BN monolayer. We find that the O 2pz orbital has both symmetry and energy matching to the Ge 4pz orbital, which promises a strong coupling. The introduction of side-by-side O to Ge donor can effectively push up the donor level by the formation of another sacrificial deep level. We discover that a Ge-O2 trimer brings the extremely shallow donor level and very low ionization energy. By low-pressure chemical vapor deposition method, we obtain the in-situ Ge-O doping in h-BN monolayer and successfully achieve both through-plane (~100 nA) and in-plane (~20 nA) n-type conduction. We fabricate a vertically-stacked n-hBN/p-GaN heterojunction and show distinct rectification characteristics. The sacrificial impurity coupling method provides a highly viable route to overcome the n-type limitation of h-BN and paves the way for the future 2D optoelectronic devices.

Light emitting diodes (LEDs) are ubiquitous in our daily life nowadays. Among them, ultraviolet LEDs are unique because of their wide range of potential applications, spanning from biomedicine, env...

Monolayer two-dimensional transition-metal dichalcogenides, such as tungsten disulfide (WS2), are regarded as promising candidates for optoelectronic and electronic applications. Although theoretic...

Structural and electronic properties of magnesium zinc oxide alloy with different Mg content and different configurations are studied by density functional theory. The energy track of rocksalt and wurtzite phases of MgZnO with different Mg content indicates that below 63% the wurtzite phase is energetically stable and above 63% the rocksalt phase is stable. Distribution of Mg in the MgZnO alloy is important to understand the phase segregation. By analyzing the distribution of Mg in the MgZnO alloy, we find that the energy required for two Mg to stay together is slightly larger than that for two Mg to stay apart, meaning that Mg has the potential to be uniformly distributed in the MgZnO alloy. By comparing with other dopants, we find that Mg introduces smaller lattice distortion. The corresponding electronic properties are studied by analyses of the density of state and the band structure. From the decomposed-projected band structure, we find that the energy level of O 2p orbitals is modulated to lower energy by introducing Mg, indicating that the enlargement of the band gap is partly caused by the subsidence of the valence band. For comparison, Cd modulates O 2p orbitals to a higher energy level, consistent with the presence of a narrow band gap.

The structural and optoelectronic properties of a MoS2-based heterostructure with a MoS2 monolayer stacked on a ZnO monolayer (g-ZnO) are calculated by first-principle simulations. MoS2/g-ZnO is a typical type II, indirect-bandgap van der Waals heterostructure. With the coupling interaction in the MoS2/g-ZnO heterostructure, the bandgap reduces with respect to both individual sheets, resulting in broadening of the absorption edges towards visible and near-infrared regions. For application in water splitting, the energy levels of the conduction-band minimum and valence-band maximum of the heterostructure are respectively high enough for water reduction and low enough for water oxidation, making this a promising functional material. For the MoS2 monolayer, the photocatalyst efficiency is limited by the high recombination rate of photogenerated electron–hole pairs. On the contrary, for the MoS2/g-ZnO van der Waals heterostructure, a large built-in electric field is formed at the interface, effectively facilitating separation of photogenerated electron–hole pairs and promoting its photocatalytic efficiency. This indicates that such MoS2/g-ZnO van der Waals heterostructures possess great prospects for application in photocatalytic and photovoltaic devices.

Surface polarity with different crystal orientations has been demonstrated as a crucial parameter in determining the physical properties and device applications in many transition metal oxide and semiconductor compound systems. The influences of surface polarity on electronic structures in nitrogen-incorporated ZnO lattices have been investigated in the present work. The successful doping of nitrogen atoms in ZnO lattices is suggested by the existence of N-related chemical bonds obtained from X-ray photoelectron spectroscopy analysis where a pronounced N–Zn peak intensity has been observed in the (000\bar 1)-terminated polar ZnO compound compared with the (10\bar 10)-terminated nonpolar ZnO compound. An energy shift of the valence band maximum towards the Fermi level has been resolved for both polar and nonpolar ZnO lattices, whereas a charge redistribution of the O 2phybridized states is only resolved foro-plane ZnO with a polar surface. Angular-dependent X-ray absorption analyses at the OK-edge reveal enhanced surface-state contributions and asymmetric O 2porbital occupations in the (000\bar 1)-terminatedo-plane ZnO compound. The results shed light on the efficient nitrogen doping in ZnO lattices with polar surfaces. The comprehensive electronic structure investigations of correlations between impurity doping and surface polarity in ZnO lattices may also offer guidance for the material design in other transition metal oxide and semiconductor systems.

Magneto-optical (MO) properties of the bilayed Au/BIG and trilayered Au/BIG/Au magneto-plasmonic crystals (MPCs) were analyzed by the finite-difference time-domain method. In contrast to the low deflection angle and transmission of the smooth thin film, all the heterostructures with perforated holes in the top Au film displayed a similar trend with two strong resonant bands in Faraday rotation and transmittance in the near infrared wavelength range. The bands and electric distribution relative to the component and hole structure were revealed. The MPC with plasmonic hexagonal holes was found to own superior Faraday effects with distinctive anisotropy. The evolution of the resonant bands with the size and period of hexagonal holes, the thickness of different layers, and the incident light polarization was illustrated. The Faraday rotation of the optimized bilayed and trilayered hexagonal MPCs was improved 15.3 and 17.5 times, and the transmittance was enhanced 12.1 and 11.1 folds respectively at the resonant wavelength in comparison to the continuous Au/BIG film, indicating that the systems might find potential application in MO devices.

Achieving high-efficient spin injection in semiconductors is critical for developing spintronic devices. Although a tunnel spin injector is typically used, the construction of a high-quality tunnel barrier remains a significant challenge due to the large lattice mismatch between oxides and semiconductors. In this work, van der Waals h-BN films with the atomically flat interface were engaged as the tunnel barrier to achieve high spin polarization in GaN, and the spin injection and transport in GaN were investigated systematically. Based on the Hanle precession and magnetic resistance measurements, CoFeB was determined as an optimal spin polarizer, bilayer h-BN tunnelling barrier was proven to yield a much higher spin polarization than the case of monolayer, and appropriate carrier concentration as well as higher crystal equality of n-GaN could effectively reduce the defect-induced spin scattering to improve the spin transport. The systematic understanding and the high efficiency of spin injection in this work may pave the way to the development of physical connotations and the applications of semiconductor spintronics.

A systematic study was carried out for strain-induced microscale compositional pulling effect on the structural and optical properties of high Al content AlGaN multiple quantum wells (MQWs). Investigations reveal that a large tensile strain is introduced during the epitaxial growth of AlGaN MQWs, due to the grain boundary formation, coalescence and growth. The presence of this tensile strain results in the microscale inhomogeneous compositional pulling and Ga segregation, which is further confirmed by the lower formation enthalpy of Ga atom than Al atom on AlGaN slab using first principle simulations. The strain-induced microscale compositional pulling leads to an asymmetrical feature of emission spectra and local variation in emission energy of AlGaN MQWs. Because of a stronger three-dimensional carrier localization, the area of Ga segregation shows a higher emission efficiency compared with the intrinsic area of MQWs, which is benefit for fabricating efficient AlGaN-based deep-ultraviolet light-emitting diode.

The external quantum efficiency of a high-Al content (0.6) AlGaN deep-ultraviolet (DUV) light-emitting diode is typically below 1% in the sub-250 nm wavelength range. One of the main reasons for this low efficiency is the fundamental properties of high-Al content AlGaN comprising the transverse-magnetic (TM)-dominant emission and low light extraction due to the total internal reflection (TIR). This work demonstrates a truncated pyramid nanostructure with fine-tuned multiple facets in an (AlN)