scholarly journals Analysis of Electrical Characteristics of Pd/n-Nanocarbon/p-Si Heterojunction Diodes: By C-V-f and G/w-V-f

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Abdelrahman Zkria ◽  
Eslam Abubakr ◽  
Phongsaphak Sittimart ◽  
Tsuyoshi Yoshitake
Keyword(s):  
Series Resistance ◽  
Lattice Structure ◽  
Wide Band ◽  
Interface States ◽  
Periodic Lattice ◽  
Hydrogen Atoms ◽  
Si Substrates ◽  
Ultrananocrystalline Diamond ◽  
Wide Range ◽  
Heterojunction Diodes

Diamond films are candidate for a wide range of applications, due to their wide band gap, high thermal conductivity, and chemical stability. In this report, diamond-based heterojunction diodes (HJDs) were fabricated by growing n-type nanocarbon composite in the form of nitrogen-doped ultrananocrystalline diamond/amorphous carbon (UNCD/a-C:H:N) films onto p-type Si substrates. X-ray photoemission and the Fourier transform infrared spectroscopies were employed to examine the contribution of nitrogen atoms from the gas phase into the deposited films. The results indicate the incorporation of nitrogen atoms into the grain boundaries of UNCD/a-C:H film by replacing hydrogen atoms. The capacitance- (C-V-f), conductance- (G/ω-V-f), and series resistance-voltage characteristics of the fabricated Pd/n-(UNCD/a-C:H:N)/p-Si HJDs were studied in the frequency range of 40 kHz-2 MHz. The existence of interface states (Nss) and series resistance (Rs) were attributed to the interruption of the periodic lattice structure at the surface of the fabricated junction as well as the defects on the (UNCD/a-C:H:N)/Si interface. By increasing the frequency (≥500 kHz), the Nss reveals an almost frequency-independent behavior, which indicates that the charges at the interface states cannot follow ac signal at higher frequency. The obtained results demonstrated that the UNCD/a-C:H:N is a promising n-type semiconductor for diamond-based heterostructure diodes.

THE EFFECT OF ETCHING TIME ON RECTIFYING CHARACTERISTIC IN SnO2/p-Si AND SnO2/p-PoSi HETEROJUNCTION SCHOTTKY DIODES

2013 ◽  
Vol 27 (08) ◽  
pp. 1350051 ◽  
Author(s):  
ALIREZA BIARAM ◽  
HOSEIN ESHGHI
Keyword(s):  
Data Analysis ◽  
Series Resistance ◽  
Schottky Diodes ◽  
Thermionic Emission ◽  
Etching Time ◽  
Spray Pyrolysis Method ◽  
Porous Si ◽  
Si Substrates ◽  
Pyrolysis Method ◽  
Heterojunction Diodes

We have fabricated SnO 2/p- Si and SnO 2/p- PoSi heterojunction diodes by spray pyrolysis method. To prepare porous Si substrates, the etching time was varied from 10 to 20 and 30 mins. In these samples, the SEM micrographs showed a distributed pore areas surrounded by columnar walls with various height. The data analysis of the rectified I–V characteristic, using thermionic emission Schottky diode theory, showed that although the barrier height is about 0.5–0.6 eV in all samples other two important diode parameters, i.e. the ideality factor n and the series resistance rs, are strongly etching time-dependant and are increased with increasing the etching time.

Epitaxial ferroelectric thin films

1994 ◽  
Vol 52 ◽  
pp. 572-573
Author(s):  
S. G. Ghonge ◽  
E. Goo ◽  
R. Ramesh ◽  
R. Haakenaasen ◽  
D. K. Fork
Keyword(s):  
Single Crystal ◽  
Work Function ◽  
Nonvolatile Memory ◽  
Ferroelectric Properties ◽  
Electrical Contact ◽  
Memory Devices ◽  
Ferroelectric Films ◽  
Si Substrates ◽  
Electro Optic ◽  
Wide Range

Microstructure of epitaxial ferroelectric/conductive oxide heterostructures on LaAIO3(LAO) and Si substrates have been studied by conventional and high resolution transmission electron microscopy. The epitaxial films have a wide range of potential applications in areas such as non-volatile memory devices, electro-optic devices and pyroelectric detectors. For applications such as electro-optic devices the films must be single crystal and for applications such as nonvolatile memory devices and pyroelectric devices single crystal films will enhance the performance of the devices. The ferroelectric films studied are Pb(Zr0.2Ti0.8)O3(PLZT), PbTiO3(PT), BiTiO3(BT) and Pb0.9La0.1(Zr0.2Ti0.8)0.975O3(PLZT).Electrical contact to ferroelectric films is commonly made with metals such as Pt. Metals generally have a large difference in work function compared to the work function of the ferroelectric oxides. This results in a Schottky barrier at the interface and the interfacial space charge is believed to responsible for domain pinning and degradation in the ferroelectric properties resulting in phenomenon such as fatigue.

scholarly journals Hybrid ZnO/MoS2 Core/Sheath Heterostructures for Photoelectrochemical Water Splitting

Applied Nano ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 148-161
Author(s):  
Katerina Govatsi ◽  
Aspasia Antonelou ◽  
Labrini Sygellou ◽  
Stylianos G. Neophytides ◽  
Spyros N. Yannopoulos
Keyword(s):  
Visible Light ◽  
Wide Band ◽  
Nanowire Arrays ◽  
Maximum Efficiency ◽  
Light Illumination ◽  
Wide Band Gap ◽  
Long Term Stability ◽  
Visible Light Illumination ◽  
Nanowire Surface ◽  
Wide Range

The rational synthesis of semiconducting materials with enhanced photoelectrocatalytic efficiency under visible light illumination is a long-standing issue. ZnO has been systematically explored in this field, as it offers the feasibility to grow a wide range of nanocrystal morphology; however, its wide band gap precludes visible light absorption. We report on a novel method for the controlled growth of semiconductor heterostructures and, in particular, core/sheath ZnO/MoS2 nanowire arrays and the evaluation of their photoelectrochemical efficiency in oxygen evolution reaction. ZnO nanowire arrays, with a narrow distribution of nanowire diameters, were grown on FTO substrates by chemical bath deposition. Layers of Mo metal at various thicknesses were sputtered on the nanowire surface, and the Mo layers were sulfurized at low temperature, providing in a controlled way few layers of MoS2, in the range from one to three monolayers. The heterostructures were characterized by electron microscopy (SEM, TEM) and spectroscopy (XPS, Raman, PL). The photoelectrochemical properties of the heterostructures were found to depend on the thickness of the pre-deposited Mo film, exhibiting maximum efficiency for moderate values of Mo film thickness. Long-term stability, in relation to similar heterostructures in the literature, has been observed.

scholarly journals Fabrication and Compressive Behavior of a Micro-Lattice Composite by High Resolution DLP Stereolithography

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 785
Author(s):  
Chow Shing Shin ◽  
Yu Chia Chang
Keyword(s):  
High Resolution ◽  
Lattice Structure ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Dip Coating ◽  
Unit Cell ◽  
Digital Light Processing ◽  
Unit Cell Size ◽  
Wide Range ◽  
And Performance

Lattice structures are superior to stochastic foams in mechanical properties and are finding increasing applications. Their properties can be tailored in a wide range through adjusting the design and dimensions of the unit cell, changing the constituent materials as well as forming into hierarchical structures. In order to achieve more levels of hierarchy, the dimensions of the fundamental lattice have to be small enough. Although lattice size of several microns can be fabricated using the two-photon polymerization technique, sophisticated and costly equipment is required. To balance cost and performance, a low-cost high resolution micro-stereolithographic system has been developed in this work based on a commercial digital light processing (DLP) projector. Unit cell lengths as small as 100 μm have been successfully fabricated. Decreasing the unit cell size from 150 to 100 μm increased the compressive stiffness by 26%. Different pretreatments to facilitate the electroless plating of nickel on the lattice structure have been attempted. A pretreatment of dip coating in a graphene suspension is the most successful and increased the strength and stiffness by 5.3 and 3.6 times, respectively. Even a very light and incomplete nickel plating in the interior has increase the structural stiffness and strength by more than twofold.

Topology, Shape, and Size Optimization of Additively Manufactured Lattice Structures Based on the Superformula

2018 ◽  
Author(s):  
Andrea Nessi ◽  
Tino Stanković
Keyword(s):  
Lattice Structure ◽  
Lightweight Design ◽  
Mathematical Formulation ◽  
Lattice Structures ◽  
Structural Synthesis ◽  
Normal Surface ◽  
Technical Problems ◽  
Wide Range ◽  
Tetrahedral Meshing

This paper investigates the application of Superformula for structural synthesis. The focus is set on the lightweight design of parts that can be realized using discrete lattice structures. While the design domain will be obtained using the Superformula, a tetrahedral meshing technique will be applied to this domain to generate the topology of the lattice structure. The motivation for this investigation stems from the property of the Superformula to easily represent complex biological shapes, which opens a possibility to directly link a structural synthesis to a biomimetic design. Currently, numerous results are being reported showing the development of a wide range of design methods and tools that first study and then utilize the solutions and principles from the nature to solve technical problems. However, none of these methods and tools quantitatively utilizes these principles in the form of nature inspired shapes that can be controlled parametrically. The motivation for this work is also in part due to the mathematical formulation of the Superformula as a generalization of a superellipse, which, in contrast to the normal surface modeling offers a very compact and easy way to handle set of rich shape variants with promising applications in structural synthesis. The structural synthesis approach is organized as a volume minimization using Simulated Annealing (SA) to search over the topology and shape of the lattice structure. The fitness of each of candidate solutions generated by SA is determined based on the outcome of lattice member sizing for which an Interior Point based method is applied. The approach is validated with a case study involving inline skate wheel spokes.

scholarly journals Facile Fabrication of Multifunctional ZnO Urchins on Surfaces

2018 ◽  
Vol 2 (4) ◽  
pp. 74 ◽  
Author(s):  
Abinash Tripathy ◽  
Patryk Wąsik ◽  
Syama Sreedharan ◽  
Dipankar Nandi ◽  
Oier Bikondoa ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Surface Density ◽  
Room Temperature ◽  
High Surface ◽  
Secondary Growth ◽  
Water Contact ◽  
Growth Step ◽  
Si Substrates ◽  
Wide Range

Functional ZnO nanostructured surfaces are important in a wide range of applications. Here we report the simple fabrication of ZnO surface structures at near room temperature with morphology resembling that of sea urchins, with densely packed, μm-long, tapered nanoneedles radiating from the urchin center. The ZnO urchin structures were successfully formed on several different substrates with high surface density and coverage, including silicon (Si), glass, polydimethylsiloxane (PDMS), and copper (Cu) sheets, as well as Si seeded with ZnO nanocrystals. Time-resolved SEM revealed growth kinetics of the ZnO nanostructures on Si, capturing the emergence of “infant” urchins at the early growth stage and subsequent progressive increases in the urchin nanoneedle length and density, whilst the spiky nanoneedle morphology was retained throughout the growth. ε-Zn(OH)2 orthorhombic crystals were also observed alongside the urchins. The crystal structures of the nanostructures at different growth times were confirmed by synchrotron X-ray diffraction measurements. On seeded Si substrates, a two-stage growth mechanism was identified, with a primary growth step of vertically aligned ZnO nanoneedle arrays preceding the secondary growth of the urchins atop the nanoneedle array. The antibacterial, anti-reflective, and wetting functionality of the ZnO urchins—with spiky nanoneedles and at high surface density—on Si substrates was demonstrated. First, bacteria colonization was found to be suppressed on the surface after 24 h incubation in gram-negative Escherichia coli (E. coli) culture, in contrast to control substrates (bare Si and Si sputtered with a 20 nm ZnO thin film). Secondly, the ZnO urchin surface, exhibiting superhydrophilic property with a water contact angle ~ 0°, could be rendered superhydrophobic with a simple silanization step, characterized by an apparent water contact angle θ of 159° ± 1.4° and contact angle hysteresis ∆θ < 7°. The dynamic superhydrophobicity of the surface was demonstrated by the bouncing-off of a falling 10 μL water droplet, with a contact time of 15.3 milliseconds (ms), captured using a high-speed camera. Thirdly, it was shown that the presence of dense spiky ZnO nanoneedles and urchins on the seeded Si substrate exhibited a reflectance R < 1% over the wavelength range λ = 200–800 nm. The ZnO urchins with a unique morphology fabricated via a simple route at room temperature, and readily implementable on different substrates, may be further exploited for multifunctional surfaces and product formulations.

scholarly journals Development and Application of Resistance Strain Force Sensors

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5826
Author(s):  
Yinming Zhao ◽  
Yang Liu ◽  
Yongqian Li ◽  
Qun Hao
Keyword(s):  
Stress Transfer ◽  
Wide Band ◽  
Resistance Strain ◽  
Current Status ◽  
Force Sensors ◽  
Technical Requirements ◽  
Creep Effect ◽  
Wide Range ◽  
Sustained Loads ◽  
Recent Developments

Resistance strain force sensors have been applied to monitor the strains in various parts and structures for industrial use. Here, we review the working principles, structural forms, and fabrication processes for resistance strain gauges. In particular, we focus on recent developments in resistance stress transfer for resistance strain force sensors and the creep effect due to sustained loads and/or temperature variations. Various error compensation methods to reduce the creep effect are analyzed to develop a metrology standard for resistance strain force sensors. Additionally, the current status of carbon nanotubes (CNTs), silicon carbide (SiC), gallium nitride (GaN), and other wide band gap semiconductors for a wide range of strain sensors are reviewed. The technical requirements and key issues of resistance strain force sensors for future applications are presented.

Growth of Vertically Aligned InGaN Nanorod Arrays on p-Type Si Substrates for Heterojunction Diodes

2010 ◽  
Vol 10 (12) ◽  
pp. 8139-8144 ◽  
Author(s):  
Kemin Wu ◽  
Tao Han ◽  
Kai Shen ◽  
Bo Liu ◽  
Ting Peng ◽  
...  
Keyword(s):  
Nanorod Arrays ◽  
Si Substrates ◽  
Vertically Aligned ◽  
Heterojunction Diodes

scholarly journals Evolution of tin oxide (SnO2) nanostructures synthesized by hydrothermal method

2021 ◽  
Author(s):  
AJAY PRATAP SINGH GAHLOT ◽  
Rupali Pandey ◽  
Sandeep Singhania ◽  
Arijit choudhary ◽  
Amit Garg ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Gas Sensing ◽  
Hydrothermal Process ◽  
Lithium Ion ◽  
Precursor Solution ◽  
Wide Band ◽  
Sno2 Nanostructures ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Wide Range

Abstract Tin oxide (SnO2), a versatile metal oxide due to its wide range of applications and its nature as an amphoteric oxide, has attracted researchers globally for many decades. Hydrothermal synthesis of wide band gap oxides with controllable nano shape and size is of primary attraction leading to myriad areas of applications such as electrodes in Lithium-ion batteries, gas sensing, photo-catalyst etc. to name a few. In this work, we have synthesized different types of nanostructures of Tin oxide through low temperature(180oC) Hydrothermal process by varying the concentration of its precursor solution (SnCl4.5H2O) from 0.0625M to 0.25M. The characterization of as -Synthesized SnO2 done using UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X ray (EDX) and X-Ray Diffraction (XRD) confirm synthesis of tin oxide and formation of various nanostructures as a function of concentration of the precursor solution. The evolution of various shapes of nanostructures has been discussed in light of existing theories.

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