scholarly journals Combined experimental-theoretical study of electron mobility-limiting mechanisms in SrSnO3

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Tristan K. Truttmann ◽  
Jin-Jian Zhou ◽  
I-Te Lu ◽  
Anil Kumar Rajapitamahuni ◽  
Fengdeng Liu ◽  
...  
Keyword(s):  
Carrier Concentration ◽  
Room Temperature ◽  
Structural Disorder ◽  
Perovskite Oxide ◽  
Epitaxial Thin Films ◽  
Power Sources ◽  
Limited Mobility ◽  
Renewable Power ◽  
Wide Range ◽  
High Carrier Mobility

AbstractThe discovery and development of ultra-wide bandgap (UWBG) semiconductors is crucial to accelerate the adoption of renewable power sources. This necessitates an UWBG semiconductor that exhibits robust doping with high carrier mobility over a wide range of carrier concentrations. Here we demonstrate that epitaxial thin films of the perovskite oxide NdxSr1−xSnO3 (SSO) do exactly this. Nd is used as a donor to successfully modulate the carrier concentration over nearly two orders of magnitude, from 3.7 × 1018 cm−3 to 2.0 × 1020 cm−3. Despite being grown on lattice-mismatched substrates and thus having relatively high structural disorder, SSO films exhibited the highest room-temperature mobility, ~70 cm2 V−1 s−1, among all known UWBG semiconductors in the range of carrier concentrations studied. The phonon-limited mobility is calculated from first principles and supplemented with a model to treat ionized impurity and Kondo scattering. This produces excellent agreement with experiment over a wide range of temperatures and carrier concentrations, and predicts the room-temperature phonon-limited mobility to be 76–99 cm2 V−1 s−1 depending on carrier concentration. This work establishes a perovskite oxide as an emerging UWBG semiconductor candidate with potential for applications in power electronics.

scholarly journals Structural and optical properties of a revived Pb0.5Ba1.5BiVO6 perovskite oxide

2019 ◽  
Vol 09 (01) ◽  
pp. 1950004 ◽  
Author(s):  
R. K. Parida ◽  
D. K. Pattanayak ◽  
Bhagyashree Mohanty ◽  
Nimai C. Nayak ◽  
B. N. Parida
Keyword(s):  
Perovskite Structure ◽  
Room Temperature ◽  
Microstructural Analysis ◽  
Compositional Analysis ◽  
Rhombohedral Phase ◽  
Double Perovskite ◽  
Xrd Analysis ◽  
Perovskite Oxide ◽  
Dielectric Study ◽  
Wide Range

The polycrystalline ceramic Pb[Formula: see text]Ba[Formula: see text]BiVO6 manifesting the complex double perovskite structure was tailored by the conventional solid state route at a moderate temperature. Qualitative phase analysis and formation of the ceramic were affirmed by XRD analysis. The X-ray powder diffraction pattern of the compound explored at room temperature affirms the single phase formation with double perovskite structure exhibiting rhombohedral phase. Microstructural analysis of the studied compound procured from the Scanning Electron Microscope (SEM) validates the formation of dense microstructures and nonuniformly distributed grains with minimal voids. Compositional analysis was shaped through the Electron Diffraction Spectroscopy (EDS) confirming the absence of contamination of any other metals apart from the mentioned ones. Dielectric (Cr and [Formula: see text]) parameters of the compound were studied using the LCR analyzer at different temperatures and wide range of frequencies. The polarization and dielectric study affirms the presence of ferroelectricity in the material with transition temperature much above the room temperature. The tangent dielectric loss of this sample being almost minimal at room temperature attributes it to find applications in different grounds of electronics. Optical equities of the ceramic were further analyzed by the RAMAN, FTIR, UV–Vis and Photoluminescence spectroscopy.

Accumulation and Recovery of Irradiation Effects in Silicon Carbide

1998 ◽  
Vol 540 ◽  
Author(s):  
W.J. Weber ◽  
W. Jiang ◽  
S. Thevuthasan ◽  
D.E. Mecready
Keyword(s):  
Activation Energy ◽  
Damage Accumulation ◽  
Room Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Complete Recovery ◽  
Structural Disorder ◽  
Dose Dependence ◽  
Thermal Recovery ◽  
Recovery Processes ◽  
Wide Range

AbstractSingle crystals of 6H-SiC have been irradiated with a variety of ions over a wide range of fluences and temperatures. The temperature and dose dependence of damage accumulation has been investigated using in-situ Rutherford Backscattering Spectrometry in channeling geometry. At low temperatures, the accumulation of structural disorder exhibits a sigmoidal dependence on dose. At room temperature and higher, simultaneous recovery processes during irradiation significantly reduce the damage accumulation rates by up to a factor of five. Isochronal and isothermal annealing studies have been used to study the damage recovery behavior. For low defect concentrations introduced by 550 keV Si+ irradiation at 160 K, complete recovery is observed at 300 K. However, defects introduced by He+ irradiation on the Si sublattice are more difficult to anneal at room temperature, which suggests trapping of the implanted helium may inhibit defect recombination. Below room temperature, the thermal recovery of defects on the Si sublattice has an activation energy on the order of 0.3 ± 0.1 eV. Defect recovery above 570 K has an activation energy on the order of 1.5 ± 0.3 eV.

Coupling energy, meteorology, hydrology and climate science to optimize renewable power planning in West Africa

2020 ◽  
Author(s):  
Sebastian Sterl ◽  
Inne Vanderkelen ◽  
Celray James Chawanda ◽  
Nicole van Lipzig ◽  
Ann van Griensven ◽  
...  
Keyword(s):  
Natural Gas ◽  
West Africa ◽  
Wind Power ◽  
Time Scales ◽  
Capacity Expansion ◽  
West African ◽  
Coupling Energy ◽  
Power Sources ◽  
Renewable Power ◽  
Wide Range

<p>Many countries in the developing world have immense, but underexploited, renewable electricity potentials. A good example are the countries in the Economic Community of West African States (ECOWAS). Historically, renewable power generation in West Africa has focused on hydropower, which produces around 20% of the region’s overall electricity generation, with natural gas providing most of the remainder; future capacity expansion plans for the region are also focused to a large extent around gas and hydropower.</p><p> </p><p>However, dropping costs for modern renewable power sources, primarily solar photovoltaic and wind power, are expected to break the West African gas-hydro-paradigm in the near future. Given the currently low levels of generation and strongly increasing power demand in many countries, they can be seen as “greenfields” for integrating variable renewable energy (VRE) sources into stable power mixes and planning transmission capacity expansion to the benefit of VRE sources.</p><p> </p><p>Such planning requires a nuanced view of the role that different resources can play in a power mix. Solar and wind power are clean and have low environmental impact, but show pronounced diurnal and seasonal cycles, which requires increased power system flexibility across a wide range of time scales. Globally, such flexibility is currently mostly delivered by natural gas, whose use in the future must be limited to comply with the goals of the Paris Agreement. Reservoir hydropower is an alternative source of flexibility, but only if adequately managed across all involved time scales and without endangering environmental flow requirements.</p><p> </p><p>In this research, we combined energy science, meteorology, hydrology and climatology to conduct a scenario-based analysis of smart renewable expansion strategies for West Africa using the REVUB model, considering all time scales ranging from hourly to decadal (including climate change effects) and all spatial scales from point to subcontinental. We show that smart management of hydropower plants, smart designs of solar-wind mixes, and smart planning of regional interconnections can ensure reliable and stable power provision while reducing future natural gas demand and at the same time avoiding ecologically damaging hydropower overexploitation. These results have wide implications for energy policy planning far beyond West Africa, particularly in hydro-dependent developing countries.</p>

scholarly journals Turning a Liability into an Asset

2019 ◽  
Vol 2 (1) ◽  
pp. 5-13
Author(s):  
James Guild
Keyword(s):  
Energy Policy ◽  
Large Scale ◽  
High Capacity ◽  
Mineral Resources ◽  
The United States ◽  
Small Scale ◽  
Power Sources ◽  
Renewable Power ◽  
Wide Range ◽  
To Come

President Jokowi has promised to add 35 GW of power to the national grid, while the Ministry of Energy and Mineral Resources wants to source 23% of its power from renewable sources by 2025. It will be difficult to reconcile these two goals as the majority of Indonesia’s 35 GW is expected to come from high-capacity coal and gas-fired plants on Java and Sumatra. This runs the risk of both undershooting the renewables goal and neglecting the more remote provinces in eastern Indonesia that rely mainly on imported diesel fuel. With a shrewd policy aproach, this could pose an opportunity to begin developing small-scale renewable power sources – such as solar, wind, and biomass gasification – in more remote parts of Indonesia where natural resources are plentiful and large-scale fossil fuel plants are impractical. This would allow PLN to both boost the share of renewables in the energy mix and acquire experience running flexible micro-grids capable of managing diverse and decentralized energy sources. This would put Indonesia ahead of the curve, as efficient grids that can draw power from a wide range of sources will likely play a big role in the future of energy policy. If PLN continues to focus narrowly on high-capacity gas and coal plants, it will risk getting locked into an inflexible, high-carbon structure ill-suited for the needs of the 21st century. The limits of such a model are already showing in the United States. Keywords: Infrastructure, energy policy, renewables, smart grid, PLN

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

1991 ◽  
Vol 30 (01) ◽  
pp. 35-39 ◽  
Author(s):  
H. S. Durak ◽  
M. Kitapgi ◽  
B. E. Caner ◽  
R. Senekowitsch ◽  
M. T. Ercan
Keyword(s):  
Soft Tissue ◽  
Room Temperature ◽  
Normal Subjects ◽  
Left Testis ◽  
Wide Range ◽  
Activity Ratios ◽  
The Right ◽  
Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

Porphyrin-Catalyzed Oxidation of N-Substituted Tetrahydroisoquinolines to Dihydroisoquinolones

Synlett ◽  
2021 ◽  
Author(s):  
Ao Li ◽  
Bin Pan ◽  
Mu Chao ◽  
Na Wang ◽  
Yu-Long Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Air Atmosphere ◽  
Wide Range ◽  
Convenient Route ◽  
Catalyzed Oxidation

A visible-light-induced direct α-oxygenation of N-substituted tetrahydroisoquinoline derivatives has been successfully developed. Metalloporphyrin (ZnTPP) has been identified as an effective and inexpensive photocatalyst for this transformation with a wide range of substrates. This protocol provides a convenient route to afford the desired products in moderate to good yields at room temperature under air atmosphere.

scholarly journals Problems of Powering End Devices in Wireless Networks of the Internet of Things

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2417
Author(s):  
Andrzej Michalski ◽  
Zbigniew Watral
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Internet Of Things ◽  
Radio Frequency Identification ◽  
Wireless Sensor ◽  
Alternative Possibilities ◽  
The Internet ◽  
Power Sources ◽  
Wide Range ◽  
The Internet Of Things

This article presents the problems of powering wireless sensor networks operating in the structures of the Internet of Things (IoT). This issue was discussed on the example of a universal end node in IoT technology containing RFID (Radio Frequency Identification) tags. The basic methods of signal transmission in these types of networks are discussed and their impact on the basic requirements such as range, transmission speed, low energy consumption, and the maximum number of devices that can simultaneously operate in the network. The issue of low power consumption of devices used in IoT solutions is one of the main research objects. The analysis of possible communication protocols has shown that there is a possibility of effective optimization in this area. The wide range of power sources available on the market, used in nodes of wireless sensor networks, was compared. The alternative possibilities of powering the network nodes from Energy Harvesting (EH) generators are presented.

scholarly journals Plasmonic semiconductor nanogroove array enhanced broad spectral band millimetre and terahertz wave detection

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jinchao Tong ◽  
Fei Suo ◽  
Tianning Zhang ◽  
Zhiming Huang ◽  
Junhao Chu ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
High Performance ◽  
Room Temperature ◽  
Spectral Band ◽  
High Capacity ◽  
Terahertz Wave ◽  
Semiconductor Surface ◽  
Wide Range ◽  
Low Sensitivity ◽  
Air Interfaces

AbstractHigh-performance uncooled millimetre and terahertz wave detectors are required as a building block for a wide range of applications. The state-of-the-art technologies, however, are plagued by low sensitivity, narrow spectral bandwidth, and complicated architecture. Here, we report semiconductor surface plasmon enhanced high-performance broadband millimetre and terahertz wave detectors which are based on nanogroove InSb array epitaxially grown on GaAs substrate for room temperature operation. By making a nanogroove array in the grown InSb layer, strong millimetre and terahertz wave surface plasmon polaritons can be generated at the InSb–air interfaces, which results in significant improvement in detecting performance. A noise equivalent power (NEP) of 2.2 × 10−14 W Hz−1/2 or a detectivity (D*) of 2.7 × 1012 cm Hz1/2 W−1 at 1.75 mm (0.171 THz) is achieved at room temperature. By lowering the temperature to the thermoelectric cooling available 200 K, the corresponding NEP and D* of the nanogroove device can be improved to 3.8 × 10−15 W Hz−1/2 and 1.6 × 1013 cm Hz1/2 W−1, respectively. In addition, such a single device can perform broad spectral band detection from 0.9 mm (0.330 THz) to 9.4 mm (0.032 THz). Fast responses of 3.5 µs and 780 ns are achieved at room temperature and 200 K, respectively. Such high-performance millimetre and terahertz wave photodetectors are useful for wide applications such as high capacity communications, walk-through security, biological diagnosis, spectroscopy, and remote sensing. In addition, the integration of plasmonic semiconductor nanostructures paves a way for realizing high performance and multifunctional long-wavelength optoelectrical devices.

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