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Efficient Polarization Beam Splitter Based on All-Dielectric Metasurface in Visible Region

In this paper, we present an all-dielectric gradient metasurface, composed of periodic arrangement of differently sized cross-shaped silicon nanoblocks resting on the fused silica substrate, to realize the function of polarization split in visible region. The cross-shaped silicon block arrays can induce two opposite transmission phase gradients along the x-direction for the...

Tuning Electronic Properties of Blue Phosphorene/Graphene-Like GaN van der Waals Heterostructures by Vertical External Electric Field

The structural and electronic properties of a monolayer and bilayer blue phosphorene/graphene-like GaN van der Waals heterostructures are studied using first-principle calculations. The results show that the monolayer-blue phosphorene/graphene-like GaN heterostructure is an indirect bandgap semiconductor with intrinsic type II band alignment. More importantly, the external...

Design of a Tunable Ultra-Broadband Terahertz Absorber Based on Multiple Layers of Graphene Ribbons

We propose and numerically demonstrate an ultra-broadband graphene-based metamaterial absorber, which consists of multi-layer graphene/dielectric on the SiO2 layer supported by a metal substrate. The simulated result shows that the proposed absorber can achieve a near-perfect absorption above 90% with a bandwidth of 4.8 Thz. Owing to the flexible tunability of graphene sheet, the...

Optically Active Plasmonic Metasurfaces based on the Hybridization of In-Plane Coupling and Out-of-Plane Coupling

Plasmonic metasurfaces have attracted much attention in recent years owing to many promising prospects of applications such as polarization switching, local electric field enhancement (FE), near-perfect absorption, sensing, slow-light devices, and nanoantennas. However, many problems in these applications, like only gigahertz switching speeds of electro-optical switches, low...

Reduced Contact Resistance Between Metal and n-Ge by Insertion of ZnO with Argon Plasma Treatment

We investigate the metal-insulator-semiconductor contacts on n-Ge utilizing a ZnO interfacial layer (IL) to overcome the Fermi-level pinning (FLP) effect at metal/Ge interface and reduce the barrier height for electrons. A small conduction band offset of 0.22 eV at the interface between ZnO and n-Ge is obtained, and the ZnO IL leads to the significant reduced contact resistance...

Preparation of Glycyrrhetinic Acid Liposomes Using Lyophilization Monophase Solution Method: Preformulation, Optimization, and In Vitro Evaluation

characterization. TL and XS drafted the manuscript. All authors read and approved the final manuscript. Authors’ Information All authors (Dr. Tingting Liu, Dr. Wenquan Zhu, Dr. Cuiyan Han, Dr. Xiaoyu Sui, Chang Liu

Tunable Electric Properties of Bilayer α-GeTe with Different Interlayer Distances and External Electric Fields

Based on first-principle calculations, the stability, electronic structure, optical absorption, and modulated electronic properties by different interlayer distances or by external electric fields of bilayer α-GeTe are systemically investigated. Results show that van der Waals (vdW) bilayer α-GeTe has an indirect band structure with the gap value of 0.610 eV, and α-GeTe has...

Selective-Area Growth of Transferable InN Nanocolumns by Using Anodic Aluminum Oxide Nanotemplates

InN nanocolumn arrays were grown on c-plane sapphire with and without anodic aluminum oxide (AAO) nanotemplates. The crystalline quality of InN nanocolumns was significantly improved by selective-area growth (SAG) using AAO templates, as verified by X-ray diffraction measurements. Then, InN nanocolumns were transferred onto p-type silicon substrates after etching off the AAO...

Effects of Post-Deposition Annealing on ZrO2/n-GaN MOS Capacitors with H2O and O3 as the Oxidizers

Wan 0 Hao Wu 0 Chang Liu 0 0 Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, and School of Physics and Technology, Wuhan University , Wuhan 430072 , China GaN-based

Ultra-narrow Band Perfect Absorber and Its Application as Plasmonic Sensor in the Visible Region

We propose and numerically investigate a perfect ultra-narrowband absorber with an absorption bandwidth of only 1.82 nm and an absorption efficiency exceeding 95% in the visible region. We demonstrate that the perfect ultra-narrowband absorption is ascribed to the coupling effect induced by localized surface plasmon resonance. The influence of structural dimensions on the optical...

Two-step deposition of Al-doped ZnO on p-GaN to form ohmic contacts

Al-doped ZnO (AZO) thin films were deposited directly on p-GaN substrates by using a two-step deposition consisting of polymer assisted deposition (PAD) and atomic layer deposition (ALD) methods. Ohmic contacts of the AZO on p-GaN have been formed. The lowest sheet resistance of the two-step prepared AZO films reached to 145 Ω/sq, and the specific contact resistance reduced to 1...

Numerical Study of an Efficient Solar Absorber Consisting of Metal Nanoparticles

We propose and theoretically investigate an efficient solar light absorber based on a multilayer structure consisting of tungsten nanoparticle layers and SiO2 layers. According to our calculation, average absorbance over 94% is achieved in the wavelength range between 400 and 2500 nm for the proposed absorber. The excellent performance of the absorber can be attributed to the...

Infrared Perfect Ultra-narrow Band Absorber as Plasmonic Sensor

We propose and numerically investigate a novel perfect ultra-narrow band absorber based on a metal-dielectric-metal-dielectric-metal periodic structure working at near-infrared region, which consists of a dielectric layer sandwiched by a metallic nanobar array and a thin gold film over a dielectric layer supported by a metallic film. The absorption efficiency and ultra-narrow...

Transparent and flexible capacitors based on nanolaminate Al2O3/TiO2/Al2O3

Transparent and flexible capacitors based on nanolaminate Al2O3/TiO2/Al2O3 dielectrics have been fabricated on indium tin oxide-coated polyethylene naphthalate substrates by atomic layer deposition. A capacitance density of 7.8 fF/μm2 at 10 KHz was obtained, corresponding to a dielectric constant of 26.3. Moreover, a low leakage current density of 3.9 × 10−8 A/cm2 at 1 V has been...

The function of a 60-nm-thick AlN buffer layer in n-ZnO/AlN/p-Si(111)

ZnO films were prepared on p-Si (111) substrates by using atomic layer deposition. High-resolution x-ray diffraction (XRD), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and I-V measurements were carried out to characterize structural, electrical, and optical properties. After introducing a 60-nm-thick AlN buffer layer, the...

Room-temperature electrically pumped near-infrared random lasing from high-quality m-plane ZnO-based metal-insulator-semiconductor devices

Epitaxial m-plane ZnO thin films have been deposited on m-plane sapphire substrates at a low temperature of 200°C by atomic layer deposition. A 90° in-plane rotation is observed between the m-plane ZnO thin films and the sapphire substrates. Moreover, the residual strain along the ZnO [−12-10] direction is released. To fabricate metal-insulator-semiconductor devices, a 50-nm...

CdS quantum dot-sensitized solar cells based on nano-branched TiO2 arrays

Nano-branched rutile TiO2 nanorod arrays were grown on F:SnO2 conductive glass (FTO) by a facile, two-step wet chemical synthesis process at low temperature. The length of the nanobranches was tailored by controlling the growth time, after which CdS quantum dots were deposited on the nano-branched TiO2 arrays using the successive ionic layer adsorption and reaction method to make...

ZnO nanosheet arrays constructed on weaved titanium wire for CdS-sensitized solar cells

Ordered ZnO nanosheet arrays were grown on weaved titanium wires by a low-temperature hydrothermal method. CdS nanoparticles were deposited onto the ZnO nanosheet arrays using the successive ionic layer adsorption and reaction method to make a photoanode. Nanoparticle-sensitized solar cells were assembled using these CdS/ZnO nanostructured photoanodes, and their photovoltaic...

Blue light emission from the heterostructured ZnO/InGaN/GaN

ZnO/InGaN/GaN heterostructured light-emitting diodes (LEDs) were fabricated by molecular beam epitaxy and atomic layer deposition. InGaN films consisted of an Mg-doped InGaN layer, an undoped InGaN layer, and a Si-doped InGaN layer. Current-voltage characteristic of the heterojunction indicated a diode-like rectification behavior. The electroluminescence spectra under forward...

Enhanced band-edge photoluminescence from ZnO-passivated ZnO nanoflowers by atomic layer deposition

The ZnO nanoflowers were synthesized by reactive vapor deposition. A secondary nucleation in the stalk/leaves interface was suggested. The photoluminescence revealed that there were many oxygen vacancies in the nanoflowers. To tune the optical properties of ZnO nanoflowers, ZnO thin films with varying thicknesses were coated on the nanoflowers by atomic layer deposition, which...