Search query: semiconductor nanomaterials mathematical models

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abstract: Abstract Researchers are using different types of nanomaterials for the enhancement of the thermal performance of regular fluids such as water, kerosene oil, etc. However, these days, the researchers are more interested in hybrid nanomaterials. The purpose of this communication is to examine the stability analysis of Cu Al2O3/water hybrid nanofluid over a non linear shrinking sheet. The hybrid nanomaterials are composed of Cu and Al2O3. These hybridized nanomaterials are then dissolved in water taken as base fluid to form Cu Al2O3//water hybrid nanofluid. Mathematical analysis and modeling have been attended in the presence of viscous dissipation and suction/injection effects. The governing equations of mathematical models are transformed into self similar solutions in the form of ODEs by using similarity transformation. Solutions of the non linear ODEs are created by employing of three stage Lobatto IIIa formula which is built in BVP4C function in the MATLAB software. A comparison of the current study has been done with the preceding published literature. The distributions of velocity, temperature profiles, coefficient of skin friction and heat transfer rate are presented graphically and conferred for numerous significant parameters entering into the problem. Results revealed the existence of dual solutions for a certain range of the suction/blowing parameter. Stability analysis is also done in order to obtain dual solutions stability. The smallest eigenvalues suggest that the first solution is stable from the second solution. Hybrid nanomaterials have a high scope toward nurturing our day to day life.
author_names: Liaquat Ali Lund

Zurni Omar

Ilyas Khan

Asiful H Seikh

El-Sayed M Sherif

Kottakkaran Sooppy Nisar
title: Stability analysis and multiple solution of Cu Al2O3/H2O nanofluid contains hybrid nanomaterials over a shrinking surface in the presence of viscous dissipation
year: 2020

abstract: Significant variations in Raman shifts with decreasing material size, D, have been detected in Raman spectroscopy. In this study, we propose a simple and unified model to determine and explain the size dependent Raman shift, o(D) of low dimensional semiconductor nanomaterials. o(D) was found to be a function of bond number in a system, with an obvious decline in Raman shift observed when size dropped to the nanoscale. This arose from a decrease in coordination number, Z(D) and increase in single bond strength, e(D) The predicted results show good agreement with experimental data for a series of semiconductor nanomaterials, showing that bond number can be used to calculate Raman shifts of nanomaterials. Moreover, this theoretical model was successfully applied to both single crystals and some binary semiconductor nanomaterials. Furthermore, bond number, which is directly related to the nanomaterial shape and size, becomes the only parameter required to determine o(D) in this model, as both Z(D) and e(D) can be determined from the bond number. This indicates that the established model has the potential to determine Raman shifts of nanomaterials with different shapes and sizes.
author_names: Huawei Li

X W He

Han Xiao

H N Du

Jinlan Wang

Hong Zhang
title: Size dependent Raman shift of semiconductor nanomaterials determined using bond number and strength.
venue: Physical chemistry chemical physics PCCP
year: 2017

abstract: ABSTRACT The size and shape dependent band gap energy of semiconductor compound nanomaterials (SCNs) is formulated. The model theory is based on the cohesive energy of the nanocrystals compared to the bulk crystals. We have considered CdSe, CdTe, ZnS, ZnSe and ZnTe semiconductors compounds for the study of size and shape dependent band gap energy. It is found that the band gap energy of SCN depends upon the particle size and shape. The model predicts that the band gap energy increases as particle size of the semiconductor nanomaterials decreases. The results obtained are compared with the available experimental data, which support the validity of the model reported.
author_names: Madan Singh

Monika Goyal

Kamal Devlal
title: Size and shape effects on the band gap of semiconductor compound nanomaterials
year: 2018

abstract: Band gap energy narrowing upon doping is consider as a general phenomenon in semiconductors. However, low surface area still the main problem that limits its wide applications. Herein, incorporation of ZnO on the surface and inside the matrix of SiO2 using CTAB as structural and capping agent have prepared via sol gel wet chemical pathway. The crystalline size, structural and textural properties of the obtained samples were investigated through different techniques like XRD, SBET surface area, UV Vis spectroscopy, FESEM and TEM. The results indicate that the surface area and pore volume constant decrease by insertion of ZnO nanoparticles in the pore wall and/or above the surface of silica. In the other hand, the organic materials removal enhanced due to the existence of different types of pores ranging from microspores to wide mesoporous system. Following the nanomaterials preparation and characterizations, some experiments have done to check the effect on the organic materials like dyes removal. One of these tests is COD result, which affirm the good degradation for most of MB dye that exist in the solution. Furthermore, the scavenger study results show that the ZnO@SiO2 nanomaterials displayed good photocatalytic properties compared to the bare silica one via its charge carrier and reactive hydroxyl radicals species. The scrutinization at the features of the obtained materials enable us to offering without doubt a promising photocatalyst candidate for different applications in wastewater and water treatment.
author_names: M F Abdel Messih

Ahmed Esmail Shalan

Mohamed Fathi Sanad
title: Facile approach to prepare ZnO@SiO2 nanomaterials for photocatalytic degradation of some organic pollutant models
venue: Journal of Materials Science: Materials in Electronics
year: 2019

abstract: The distribution of constant electric current potential in case of probe measurement on anisotropic semiconductors and fields has been studied. The expressions for potential distribution have been obtained. It enables to identify the area of the probe field of the scanning microscope in case an anisotropic film is under study. The results of the research demonstrate the correlation between the size and anisotropy of specific electroconductivity and the resistance change of probe spreading in limited films.
author_names: Vladimir Filippov

Sergey Mitsuk

Sergey Luzyanin
title: Electric Field Mathematical Modelling at Probe Measurement in Anisotropic Semiconductor Films
venue: 2019 1st International Conference on Control Systems, Mathematical Modelling, Automation and Energy Efficiency (SUMMA)
year: 2019

abstract: The size and shape dependent band gap energy of semiconductor compound nanomaterials (SCNs) is formulated. The model theory is based on the cohesive energy of the nanocrystals compared to the bulk.
author_names: Madan Singh

Monika Goyal

Kamal Devlal
title: Size and shape effects on the band gap of semiconductor compound nanomaterials
year: 2017

abstract: This paper describes the development and verification of mathematical models which will approximate the electrical characteristics of Zener and/or avalanche diodes and tunnel diodes. Each model consists of a circuit of discrete components with their defining equations. The equations are in a form compatible with the digital computer language which makes the models useful in analysis and design, by computer, of electronic circuits containing these devices. The Zener diode model is basically the familiar Ebers Moll conventional diode model except that additional current sources have been added to approximate the voltage regulation when breakdown of the junction occurs. The equation for junction capacitance has been modified to model the decrease in capacitance due to avalanche in the junction. A tunnel diode model is presented which approximates the entire static characteristic, including the negative resistance region. Methods for extracting model parameters from a limited number of easily obtainable data points are developed. A method for measuring and describing junction capacitance is also presented.
author_names: Marvin E Daniel
title: Development of mathematical models of semiconductor devices for computer aided circuit analysis
year: 1967

abstract: In designing and optimizing new generation nanomaterials and related quantum devices, dissipation versus decoherence phenomena are often accounted for via local scattering models, such as relaxation time and Boltzmann like schemes. Here we show that the use of such local scattering approaches within the Wigner function formalism may lead to unphysical results, namely anomalous suppression of intersubband relaxation, incorrect thermalization dynamics, and violation of probability density positivity. Furthermore, we propose a quantum mechanical generalization of relaxation time and Boltzmann like models, resulting in nonlocal scattering superoperators that enable one to overcome such limitations.
author_names: Rita Claudia Iotti

Fabrizio Dolcini

Fausto Rossi
title: Wigner function formalism applied to semiconductor quantum devices: Need for nonlocal scattering models
year: 2017

abstract: Optically bright colloidal semiconductor nanocrystals (CSNCs) are important nanomaterials because of their potential applications such as cellular imaging and solid state lighting. The optoelectronic properties of CSNCs are strongly controlled by the chemical nature of the surface passivating ligands that are introduced during their synthesis. However, the existing LaMer growth model does not provide a clear understanding of the stage when ligands become attached onto the CSNC surface. Herein, apart from the three stage formation mechanism of CSNCs (supersaturation, nucleation, and growth) an entirely new stage solely involving surface ligand attachment onto fully grown CSNCs is now reported that controls their photoluminescence properties. Furthermore, we also demonstrate a fundamentally new surface modification approach using partially passivated CSNCs to introduce a variety of functional groups (azide, alkene, and siloxane) including photoisomerizable molecular machines (e.g. azobenzene) without th.
author_names: Meghan B Teunis

Thakshila Liyanage

Sukanta Dolai

Barry B Muhoberac

Rajesh Sardar

Mangilal Agarwal
title: Unraveling the Mechanism Underlying Surface Ligand Passivation of Colloidal Semiconductor Nanocrystals: A Route for Preparing Advanced Hybrid Nanomaterials
year: 2017

abstract: One thing in common: The formation of binary colloidal semiconductor nanocrystals from single (M(EEPPh2 )n and dual source precursors (metal carboxylates M(OOCR)n and phosphine chalcogenides such as E=PHPh2 is found to proceed through a common mechanism. For CdSe as a model system (31) P NMR spectroscopy and DFT calculations support a reaction mechanism which includes numerous metathesis equilibriums and Se exchange reactions.
author_names: Kui Yu

Xiang-Yang Liu

Qun Zeng

Mingli Yang

Jianying Ouyang

Xinqin Wang

Ye Tao
title: The formation mechanism of binary semiconductor nanomaterials: shared by single source and dual source precursor approaches.
venue: Angewandte Chemie
year: 2013