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Band gap semiconductor

Xin He, David J Singh, Patsorn Boon-On, Ming-Way Lee, Lijun Zhang
Dielectric screening plays an important role in reducing the strength of carrier scattering and trapping by point defects for many semiconductors such as the halide perovskite solar materials. However, it was rarely considered as a screen to find new electronic semiconductors. We performed a material search study using the dielectric properties as a screen to identify potential electronic materials in the class of metal-pnictide ternary sulfosalts, containing Bi or Sb. These salts are basically ionic due to the electronegativity difference between both the S and both the metal and pnictogen elements...
December 5, 2018: Journal of the American Chemical Society
Wesley J Transue, Matthew Nava, Maxwell W Terban, Jing Yang, Matthew W Greenberg, Gang Wu, Elizabeth S Foreman, Chantal L Mustoe, Pierre Kennepohl, Jonathan S Owen, Simon J L Billinge, Heather J Kulik, Christopher C Cummins
Thermolysis of a pair of dibenzo-7-phosphanorbornadiene compounds is shown to lead to differing behaviors: phosphinidene sulfide release and formation of amorphous P2 S. These compounds, t BuP(S)A (1, A = C14 H10 or anthracene; 59% isol. yield) and HP(S)A (2; 63%), are available through thionation of t BuPA and the new secondary phosphine HPA (5), which is prepared from Me2NPA in 50% yield by reaction with DIBAL-H. Phosphinidene sulfide [ t BuP=S] transfer is shown to proceed efficiently from 1 to 1,3-dimethyl-2,3-butadiene to form Diels-Alder product 3 with a zero order dependence on diene...
December 4, 2018: Journal of the American Chemical Society
Tatsuya Kameyama, Marino Kishi, Chie Miyamae, Dharmendar Kumar Sharma, Shuzo Hirata, Takahisa Yamamoto, Taro Uematsu, Martin Vacha, Susumu Kuwabata, Tsukasa Torimoto
The nonstoichiometry of I-III-VI semiconductor nanoparticles, especially the ratio of group I to group III elements, has been utilized to control their physicochemical properties. We report the solution-phase synthesis of nonstoichiometric Ag-In-S and Ag-In-Ga-S nanoparticles and results of the investigation of their photoluminescence (PL) properties in relation to their chemical compositions. While stoichiometric AgInS2 nanoparticles simply exhibited only a broad PL band originating from defect sites in the particles, a narrow band edge PL peak newly appeared with a decrease in the Ag fraction in the nonstoichiometric Ag-In-S nanoparticles...
December 3, 2018: ACS Applied Materials & Interfaces
N Babitha, L Srimathi Priya, S Rosy Christy, A Manikandan, A Dinesh, M Durka, S Arunadevi
Semiconductor ZnO samples with two different morphologies such as nanoparticles (ZnO-NPs) and nano-sheets (ZnO-NSs) was successfully prepared by microwave heating (MHM) and modified sol-gel (SGM) method, respectively using Pedalium Murex plant extract as the bio-reducing agent. Structural, purity and morphology of the samples was examined by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis. Optical property analysis and band gap calculation were carried out by UV-Visible diffuse reflectance (DRS) and photoluminescence (PL) spectroscopy techniques...
May 1, 2019: Journal of Nanoscience and Nanotechnology
Junwei Wen, Shuting Huang, Yu Sun, Zhengjie Chen, Yixiang Wang, Houbin Li, Xinghai Liu
Colorimetric oxygen indicators can be applied for non-destructive testing in packaging; especially in modified atmosphere packaging (MAP). In this paper; titanium dioxide (TiO₂) nanotube; which is used as a semiconductor photocatalyst in oxygen indicators; was synthesized via a microwave-assisted hydrothermal method. X-Ray Diffraction (XRD) was used to analyze its crystal form and Scanning Electron Microscope (SEM).to characterize its morphology. Its properties were studied using Brunauer-Emmett-Teller (BET), Diffuse Reflection Spectrum (DRS), and Bluebottle experiments...
November 29, 2018: Materials
Qadeer-Ul Hassan, Dou Yang, Jian-Ping Zhou, Yu-Xi Lei, Jing-Zhou Wang, Saif Ullah Awan
Novel multifeatured hollandite K1.46 Fe0.8 Ti7.2 O16 (KFTO) was synthesized by a simple hydrothermal method. Magnetic KFTO microrods were well controlled to long rectangular rods with pyramid-shaped tops. A KFTO growth mechanism was proposed on the basis of examining phase and morphology of the samples acquired at different reaction times. The KFTO morphology was confirmed by the calculated surface energies. The UV-vis diffuse reflectance spectra of KFTO microrods showed double absorption with band gaps of 2...
November 30, 2018: Inorganic Chemistry
Enrico Della Gaspera, Joseph Griggs, Taimur Ahmed, Sumeet Walia, Edwin L H Mayes, Arrigo Calzolari, Alessandra Catellani, Joel van Embden
Doping semiconductor nanocrystals is a powerful tool to impart new and beneficial optical and electrical properties to the host nanocrystals. Doping has been used to improve the performances of nanocrystal-based devices in applications as diverse as optics, magnetism, electronics, catalysis and sensing. In this work we present a low temperature colloidal synthesis of zinc sulfide (ZnS) nanocrystals doped with indium. Through optimization of the reaction parameters and the doping level, quantum confined (∼2 nm in size) crystalline colloids with highly tunable optical properties are achieved...
November 29, 2018: Nanoscale
Ward van der Stam, Indy du Fossé, Gianluca Grimaldi, Julius O V Monchen, Nicholas Kirkwood, Arjan J Houtepen
The photoluminescence (PL) quantum yield of semiconductor nanocrystals (NCs) is hampered by in-gap trap states due to dangling orbitals on the surface of the nanocrystals. While crucial for the rational design of nanocrystals, the understanding of the exact origin of trap states remains limited. Here, we treat CdTe nanocrystal films with different metal chloride salts and we study the effect on their optical properties with in situ spectroelectrochemistry, recording both changes in absorption and photoluminescence...
November 13, 2018: Chemistry of Materials: a Publication of the American Chemical Society
Chien-Hung Wu, Kow-Ming Chang, Yi-Ming Chen, Yu-Xin Zhang, Yu-Hsuan Tan
In the past few years, thin film transistors have a wide range of applications on display technology, material selection and quality for its active layer is critical for device performance. Traditional amorphous silicon (a-Si) silicon has a lot of advantages such as good productivity, short process and low-cost. It also has a lot of shortcomings on these applications on TFTs such as photosensitivity, light degradation, and opacity, etc. The dispute of the material based on a-Si:H as an active layer in TFT is low field effect mobility (~1 cm²/V·S) (M...
April 1, 2019: Journal of Nanoscience and Nanotechnology
Chien-Hung Wu, Kow-Ming Chang, Yi-Ming Chen, Yu-Xin Zhang, Yu-Hsuan Tan
TFT panel production process can be divided into three kinds of technology. There have amorphous silicon (a-Si), low-temperature polysilicon (LTPS) and amorphous IGZO (a-IGZO) oxide. Traditional amorphous silicon (a-Si) silicon has a lot of advantages such as good productivity, short process and low-cost. It also has a lot of shortcomings on these applications on TFTs such as photosensitivity, light degradation, and opacity, etc. The dispute of the material based on a-Si:H as an active layer in TFT is low field effect mobility (~1 cm²/V·S) (M...
April 1, 2019: Journal of Nanoscience and Nanotechnology
Wageh Swelm, Ahmed Al-Ghamdi, Asim Jilani, Javed Iqbal
The synthesis of alloyed semiconductor quantum dots has produced structures that have distinct properties in comparison with both their bulk counterparts and their parent binary semiconductor quantum dots. In this work, the quantum confined structures of a ternary alloy of CdSe1- x S x were synthesized by one-pot synthesis method in an aqueous medium at a low temperature and capped with 3-mercaptopropoionic acid. Structures of the synthesized quantum dots were investigated by energy dispersive X-ray, X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy...
November 27, 2018: Nanomaterials
Bofeng Zhang, Hong Zhang, Jiahe Lin, Xinlu Cheng
Recently, Group-V monolayer elements, especially the novel allotropes of arsenene and antimonene, have attracted significant attention. Motivated by this, we employed first principles to systemically investigate the properties of seven new allotropes of arsenene and antimonene. Through analysis of cohesive energy and phonon mode dispersion, we proved their high dynamical stability. Thermodynamics were also considered with Debye temperature, heat capacity and Gibb's free energy, which revealed their basic thermal properties and thermo-dynamic stability at ambient temperature...
November 28, 2018: Physical Chemistry Chemical Physics: PCCP
Dmitriy V Steglenko, Ruslan M Minyaev, Vladimir I Minkin, Alexander I Boldyrev
We computationally showed that by difluorination of phosphorene we can make a new material difluorphosphorane (DFP) with perfectly planar honeycomb structure out of phosphorus atoms with fluorine atoms attached to every phosphorus atom from above and below. The structure is dynamically stable. It is a semiconductor with the direct band gap of 4.51 eV and 3.88 eV for the indirect band gap. We hope that with the passivation this new DFP material if made could find many applications in nanoelectronics.
November 27, 2018: Journal of Physical Chemistry Letters
Tom Dvir, Charis H L Quay, Marco Aprili, Hadar Steinberg
We have performed device-based tunnelling spectroscopy of NbSe2 in the vortex state with magnetic field applied both parallel and perpendicular to the a-b plane. Our devices consist of layered semiconductors placed on top of exfoliated NbSe2 using the van der Waals transfer technique. At zero field, the spectrum exhibits a hard gap, and the quasiparticle peak is split into low and high energy features. The two features, associated with the effective two-band nature of superconductivity in NbSe2 , exhibit markedly distinct responses to the application of magnetic field, suggesting and order-of-magnitude difference in the spatial extent of the vortex cores of the two bands...
November 26, 2018: Nano Letters
Pooja Jamdagni, Anil Thakur, Ashok Kumar, P K Ahluwalia, Ravindra Pandey
Considering the rapid development of experimental techniques for fabricating 2D materials in recent years, various monolayers are expected to be experimentally realized in the near future. Motivated by the recent research activities focused on the honeycomb arsenene monolayers, the stability and carrier mobility of non-honeycomb and porous allotropic arsenene are determined using first principles calculations. In addition to five honeycomb structures of arsenene, a total of eight other structures are considered in this study...
November 26, 2018: Physical Chemistry Chemical Physics: PCCP
Cunhua Xu, Zhe Du, Yaoguang Huang, Mei Dong, Richeng Lin, Yuqiang Li, Biao Wang, Wei Zheng, Feng Huang
Vacuum-ultraviolet (VUV) detector equipped on satellites has extensive application in space exploration and cosmic science. For VUV detector, a semiconductor material with sufficiently wide band gap is eagerly desired. In this work, a wide-band-gap amorphous-MgGaO (a-MGO) film was epitaxially grown on n-type GaN substrate by atomic layer deposition and a p-i-n type heterojunction device for VUV detection was constructed with a-MGO film as photosensitive layer and p-type graphene as transparent conductive layer...
November 26, 2018: ACS Applied Materials & Interfaces
Chhabilal Regmi, Yuwaraj K Kshetri, Ramesh Prasad Pandey, Tae-Ho Kim, Gobinda Gyawali, Soo Wohn Lee
A visible light-induced, Cu-doped BiVO4 photocatalyst was synthesized by a microwave hydrothermal method. The photocatalytic efficiency was investigated in the degradation of model water pollutants like Methylene Blue (dye) and ibuprofen (pharmaceuticals), as well as the inactivation of Escherichia coli (bacteria). The Cu-doped BiVO4 samples showed better efficiency than undoped BiVO4 , and the 1wt.% Cu-doped BiVO4 sample showed the best efficiency. The degradation of Methylene Blue reached 95%, while the degradation of ibuprofen reached 75%, and the inactivation of E...
January 2019: Journal of Environmental Sciences (China)
Ramavath Babu, Surya Prakash Singh
All-inorganic CsPbBr3 perovskite nanocrystals are emerging as a new class of semiconductors with outstanding optoelectronic properties and great potential for various applications, such as, lasing, photon detection, photovoltaics etc. This article provides the effect of solvents on the re-precipitation of CsPbBr3 perovskite at room temperature. The results observed for CsPbBr3 perovskite in various anti-solvent showed various cubes (nano to micro size), self-assembly of nanocubes and nanorods. In addition, all the various size (nano to micro), self-assembly of nanocubes and shape-controlled nanorods exhibited band-gap tuning at the green light region...
November 25, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Xiongbin Wang, Jiahao Yu, Rui Chen
Nanocrystal quantum dots (QDs) have great potential for optoelectronic applications such as light emitting diodes and lasers due to their superior optical properties. The core-shell CdSe/CdS QDs can suppress Auger recombination effectively and enhance the emission efficiency. However, it will lead to poor photostability due to the small conduction band offset between CdSe core and CdS shell. For effective electron confinement, a thin shell of wide band gap ZnS semiconductor was grown on the CdSe/CdS core-shell QDs...
November 23, 2018: Scientific Reports
Botong Qiu, Yida Lin, Ebuka S Arinze, Arlene Chiu, Lulin Li, Susanna M Thon
Spectrally selective materials are of great interest for optoelectronic devices in which wavelength-selectivity of the photoactive material is necessary for applications such as multi-junction solar cells, narrow-band photodetectors, transparent photovoltaics, and tailored emission sources. Achieving controlled transparency or opacity within multiple wavelength bands in the absorption, reflection, and transmission spectra are difficult to achieve in traditional semiconductors that typically absorb at all energies above their electronic band gap and is generally realized by the use of external bandpass filters...
October 15, 2018: Optics Express
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