scholarly journals ANNEALING TEMPERATURES’ EFFECTS ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF Ba0.95Sr0.05TiO3 FILMS

2021 ◽  
Vol 23 (1) ◽  
pp. 31
Author(s):  
Yofentina Iriani ◽  
Fahru Nurosyid ◽  
Ratna Mayasari ◽  
Dianisa Khoirum Sandi
Keyword(s):  
Optical Properties ◽  
Annealing Temperature ◽  
Ferroelectric Material ◽  
Ferroelectric Materials ◽  
Bandgap Energy ◽  
Annealing Temperatures ◽  
Type Semiconductor ◽  
Bst Films ◽  
P Type ◽  
Quartz Substrates

ANNEALING TEMPERATURES’ EFFECTS ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF Ba0.95Sr0.05TiO3 FILMS. Ferroelectric materials, one of which is Barium Strontium Titanate (BST), can be applied for photovoltaic. Ferroelectric films function as the P-type semiconductor in the P-N junction. BST (Ba0.95Sr0.05TiO3) films have been deposited on Pt/Si (111) and quartz substrates via the CSD method prepared by spin coater. The films were annealed at various temperatures of 800 °C, 900 °C, and 1000 °C to observe the annealing temperatures' effects on the microstructure and optical properties of the BST films. From the XRD results, the intensity of diffraction peaks gets higher along with the higher annealing temperature. It thus causes the level of crystallization and the crystal size of the Ba0.95Sr0.05TiO3 films to increase. The morphology results reveal that the grains size of the Ba0.95Sr0.05TiO3 films is getting larger with the higher annealing temperature. The optical properties examined in the Ba0.95Sr0.05TiO3 films include absorbance and bandgap energy values. Values of bandgap energy show a decrease with increasing sintering temperature. The smallest bandgap energy of the Ba0.95Sr0.05TiO3 film is achieved at 1000 °C of 3.20 eV. BST films were annealed at temperature 1000 °C attained from this study can be considered as candidate for a photovoltaic ferroelectric material.

Improvement of the Specific Contact Resistance on P-Type 4H-SiC by Using a Highly P-Typed Doped 4H-SiC Layer Selectively Grown by VLS Transport

2014 ◽  
Vol 806 ◽  
pp. 57-60
Author(s):  
Nicolas Thierry-Jebali ◽  
Arthur Vo-Ha ◽  
Davy Carole ◽  
Mihai Lazar ◽  
Gabriel Ferro ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
Schottky Barrier Height ◽  
Annealing Temperature ◽  
Process Condition ◽  
Specific Contact Resistance ◽  
High Doping Level ◽  
Annealing Temperatures ◽  
Specific Contact ◽  
P Type

This work reports on the improvement of ohmic contacts made on heavily p-type doped 4H-SiC epitaxial layer selectively grown by Vapor-Liquid-Solid (VLS) transport. Even before any annealing process, the contact is ohmic. This behavior can be explained by the high doping level of the VLS layer (Al concentration > 1020 cm-3) as characterized by SIMS profiling. Upon variation of annealing temperatures, a minimum value of the Specific Contact Resistance (SCR) down to 1.3x10-6 Ω.cm2 has been obtained for both 500 °C and 800 °C annealing temperature. However, a large variation of the SCR was observed for a same process condition. This variation is mainly attributed to a variation of the Schottky Barrier Height.

Doping and Annealing Effects on the Optical Bandgap of the Nickel Doped Copper Oxide Thin Films

2021 ◽  
Vol 16 (2) ◽  
pp. 243-248
Author(s):  
Fatmah S. Bahabri ◽  
Alaa Y. Mahmoud ◽  
Wafa A. Alghameeti
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Doping Concentration ◽  
Cupric Oxide ◽  
Optical Bandgap ◽  
Visible Range ◽  
Bandgap Energy ◽  
Direct Bandgap ◽  
Annealing Temperatures ◽  
Annealing Effects

In this work, we study the optical properties of the Nickel doped cupric oxide Ni-CuO thin films with Ni various doping concentrations (0, 20, 30, 50, 70, and 80%), at two different annealing temperatures; 200 and 400 °C. The absorbance and optical bandgap for the films are calculated and compared. We find that all films exhibit clear peaks in the visible range, with the increase in the absorptivity via increasing both annealing and Ni concentration. We also find that the annealing affects the shape of the absorbance peaks to be narrowed and blue shifted. Investigation on the direct bandgap energy shows that all films exhibit large direct gap; ranging from 3.87 to 4.01 eV. For non-annealed films, direct bandgap increases with increasing the Ni concentration, while for the annealed samples, the direct bandgap generally decreases by annealing, and with increasing the doping concentration. For the indirect bandgap analysis, the calculated values of the bandgap are ranging from 0.62 to 1.96 eV. We find that for non-annealed films, the indirect bandgap increases with increasing the doping concentration, while after annealing, the bandgap decreases with increasing the doping concentration for the annealing at 200 and 400 °C, with more decreasing in the gap at 400 °C.

Structural and Optical Properties of the Thermally Stable Amorphous Si1−xBx Alloy.

1993 ◽  
Vol 297 ◽  
Author(s):  
Johan R. A. Carlsson ◽  
X.H. Li ◽  
S.F. Gong ◽  
H.T.G. Hentzell
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Annealing Temperature ◽  
High Vacuum ◽  
Vacuum System ◽  
Structural And Optical Properties ◽  
Microstructural Alterations ◽  
Amorphous Si ◽  
Means Of Transmission ◽  
Quartz Substrates

Thin amorphous Si1−xBx films were co-evaporated onto pre-oxidized (100) Si wafers and quartz substrates, by using a high vacuum system with 2 electron guns. Films were deposited in a composition range from x=0 to x=0.5. In order to study how the structural and optical properties depended on concentration and annealing temperature, heat treatments were carried out at temperatures from 400 up to 1000°C. The films were characterized by means of transmission electron microscopy (TEM), Auger electron spectroscopy (AES), and light absorption spectrophotometry. It is shown that the amorphous Si1−xBx alloy is stable up to 1000°C at certain compositions and that the optical band gap of the alloy increases gradually with increasing annealing temperature up to 700 - 900°C, and then increases rapidly when annealed at a higher temperature by about 0.5 eV. These changes can be associated with microstructural alterations. The relationship between the microstructure and the band gap of the films is discussed.

First-Principles Study of Electronic Structure and Optical Properties of V-Doped CrSi2

2015 ◽  
Vol 1104 ◽  
pp. 125-130 ◽  
Author(s):  
Fang Gui ◽  
Shi Yun Zhou ◽  
Wan Jun Yan ◽  
Chun Hong Zhang ◽  
Shao Bo Chen
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Density Of States ◽  
Density Functional ◽  
Partial Density ◽  
Optical Parameters ◽  
Total Density ◽  
Type Semiconductor ◽  
Refractive Index Increase ◽  
P Type

The electronic structure and optical properties of V-doped CrSi2 have been calculated by using the first-principle peudo-potential plane-wave method based on the density functional theory.The parameters and properties of structure were given and the theory data were offered to research the effect of V doping into CrSi2. The calculations of energy band structure, total density of states, partial density of states of V-doped CrSi2were analysed. Fermi level enters into valence band which makes the V-doped CrSi2to be p-type semiconductor that improves the electrical conductivity of material. Additionally, the optical parameters of V-doped CrSi2were also discussed. It was found that both static dielectric constant and static refractive index increase after doping.

scholarly journals First-Principles Calculations of the Structural, Electronic and Optical Properties of Yttrium-Doped SnO2

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nabil Beloufa ◽  
Youcef Chechab ◽  
Souad Louhibi-Fasla ◽  
Abbes Chahed ◽  
Samir Bekheira ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Level Shifts ◽  
Type Semiconductor ◽  
Direct Band ◽  
P Type ◽  
Theoretical Results ◽  
Good Agreement

Abstract We use FP-LAPW method to study structural, electronic, and optical properties of the pure and Y-doped SnO2. The results show that by Y doping of SnO2 the band gaps are broadened, and still direct at Γ-point. For pure SnO2 material, the obtained values of the direct band gap are 0.607 eV for GGA-PBE and 2.524 eV for GGATB-mBJ, respectively. This later is in good agreement with the experimental data and other theoretical results. The Fermi level shifts into the valence band and exhibits p-type semiconductor character owing mainly from the orbital 4d-Y. Additionally, the calculated optical properties reveal that all concentrations are characterized by low reflectivity and absorption via wavelength λ (nm) in the visible light and near-infrared (NIR) ranges, which leads to a redshift in the optical transparency.

Exploration on electronic and optical properties of two-dimensional GaN-doped with Be, Mg, Zn

2020 ◽  
Vol 34 (20) ◽  
pp. 2050195
Author(s):  
Gang Li ◽  
Lei Liu ◽  
Jian Tian
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Of States ◽  
First Principles ◽  
High Energy ◽  
Low Energy ◽  
Two Dimensional ◽  
Electronic And Optical Properties ◽  
Type Semiconductor ◽  
P Type

To explore the variation on p-type-doped two-dimensional GaN, we calculate electronic and optical properties of buckled two-dimensional GaN-doped with p-type doping elements including Be, Mg and Zn atom by using first-principles. The results indicate that doping process of two-dimensional GaN after Be is most easily compared with Mg- and Zn-doped models. Band of doped two-dimensional GaN moves toward high energy end and it becomes a p-type semiconductor from the results of band structure and density of states, which may be caused by orbitals hybridization from dopants. Band gap and work function of doped two-dimensional GaN are both declined, which is beneficial for escape of electrons. Analysis of optical properties shows that they are sensitive and adjustable in doped two-dimensional GaN. Doping of Be, Mg and Zn atoms would have an important effect on optical characteristics of two-dimensional GaN at low-energy region.

Changes in Optical Properties of GaAsN During Annealing

2005 ◽  
Vol 891 ◽  
Author(s):  
Ting Liu ◽  
Sandeep Chandril ◽  
Eric D. Schires ◽  
Nianqiang Wu ◽  
Xinqi Chen ◽  
...  
Keyword(s):  
Optical Properties ◽  
Molecular Beam Epitaxy ◽  
Quantum Dot ◽  
Photoelectron Spectroscopy ◽  
Molecular Beam ◽  
Annealing Temperature ◽  
Emission Spectra ◽  
X Ray ◽  
Annealing Temperatures ◽  
Gaas Substrates

ABSTRACTGaAs1−xNx layers and quantum dot-like structures were grown on (100) GaAs substrates by molecular beam epitaxy. The dependence of photoluminescence emission spectra on annealing temperature is consistent with literature at lower temperatures but after annealing at 750 °C a net red-shift is consistently observed. X-ray photoelectron spectroscopy measurements indicate that for different annealing times and temperatures, the nitrogen and arsenic surface concentrations changed compared to that of as-grown samples, specifically arsenic is lost from the material. Raman measurements are consistent with the trends in photoluminescence and also suggest the loss of arsenic occurs at higher annealing temperatures in both samples capped with GaAs and uncapped samples.

Half-Metallic and Optical Properties of Cu and Cr Codoped AlN

2013 ◽  
Vol 842 ◽  
pp. 205-209
Author(s):  
Yu Qin Fan ◽  
Xue Yao
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Hole Concentration ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Metallic Material ◽  
Half Metallic ◽  
Type Semiconductor ◽  
P Type

The Half-metallic and optical properties of wurtzite Cu and Cr codoped AlN were investigated by first-principles calculation based on density functional theory (DFT) using the generalized gradient approximation (GGA) for the exchange-correlation potential. It is shown that the Cu and Cr codoped AlN is a typical half-metallic material at the equilibrium lattice constant. As a p-type semiconductor, there exhibits higher hole concentration in Cu and Cr codoped AlN comparing with Cu doped AlN or Cr doped AlN, which indicates a significant increase in TC. This result suggests that it is possible to achieve high TC materials by Cu and Cr codoped AlN. In addition, the band gap of Cu and Cr codoped AlN is reduced and the absorption ability to ultraviolet light is expanded obviously, a noticeable red-shift of the absorption spectra edge is observed in the Cu and Cr codoped system and two new absorption peaks appear at around 28 nm and 225 nm.

scholarly journals Cathodic Electrodeposition and Characterization of ni3se2 thin Films

2017 ◽  
Vol 21 (1) ◽  
pp. 19 ◽  
Author(s):  
K Anuar ◽  
Z Zainal ◽  
N Saravanan ◽  
A.R Kartini
Keyword(s):  
Thin Films ◽  
Titanium Substrate ◽  
Linear Sweep Voltammetry ◽  
Xrd Analysis ◽  
Band Gap Energy ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
Cathodic Electrodeposition ◽  
Type Semiconductor ◽  
P Type

Nickel selenide thin films have been potentiostatically electrodeposited on titanium substrate at room temperature from aqueous solution containing Ni-EDTA and Na2SeO3. Various deposition potentials were attempted in order to determine the optimum electrodeposition potential. The films were characterised using x-ray diffraction analysis (XRD) and the photoactivity of the electrosynthesised films were studied using linear sweep voltammetry (LSV). The band-gap energy was determined using UV-visible spectroscopy. The XRD analysis indicated the formationof polycrystalline Ni3Se2. The film exhibited p-type semiconductor behaviour with good photosensitivity. The bandgap energy (Eg) was about 1.4eV.

scholarly journals Effect of Annealing Temperature on the Optical Properties of ZnO Nanoparticles

2013 ◽  
Vol 23 ◽  
pp. 37-47 ◽  
Author(s):  
Raid A. Ismail ◽  
Nadir F. Habubi ◽  
Hussam R. Abid
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Wavelength Range ◽  
Zno Nanoparticles ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Optical Measurements ◽  
Zno Films ◽  
Casting Technique ◽  
Quartz Substrates

In this work, ZnO films were prepared by drop casting technique. The films were deposited on quartz substrates under different annealing time (15, 30, 45 and 60 min.) at a constant temperature (800 °C). The optical properties were achieved by measuring the absorbance and transmittance spectra in the wavelength range (200-900) nm. It was found that the absorbance decreases while transmission increases as the annealing time increases, while the reflectance decreases as the annealing time increases. The optical measurements indicate the kind of transition which was a direct allowed with an average band gap energies lie between 3.3 eV and 3.54 eV with the change of annealing time.

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