Impact of Cd-addition upon optical properties and dispersion parameters of thermally evaporated CdxZn1-xSe films: Discussions on bandgap engineering, conduction and valence band positions

Optik ◽  
2020 ◽  
Vol 212 ◽  
pp. 164681 ◽  
Author(s):  
Ahmed Saeed Hassanien ◽  
R. Neffati ◽  
K.A. Aly
Keyword(s):  
Optical Properties ◽  
Valence Band ◽  
Bandgap Engineering ◽  
Dispersion Parameters

scholarly journals Valence Band Mixing in GaAs/AlGaAs Quantum Wells Adjacent to Self-Assembled InAlAs Antidots

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Takuya Kawazu
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Valence Band ◽  
Energy Barrier ◽  
Heavy Hole ◽  
Electronic States ◽  
Light Hole ◽  
Photoluminescence Excitation ◽  
Band Mixing ◽  
Valence Band Mixing

Optical properties of GaAs/AlGaAs quantum wells (QWs) in the vicinity of InAlAs quantum dots (QDs) were studied and compared with a theoretical model to clarify how the QD strain affects the electronic states in the nearby QW. In0.4Al0.6As QDs are embedded at the top of the QWs; the QD layer acts as a source of strain as well as an energy barrier. Photoluminescence excitation (PLE) measurements showed that the QD formation leads to the increase in the ratio Ie-lh/Ie-hh of the PLE intensities for the light hole (lh) and the heavy hole (hh), indicating the presence of the valence band mixing. We also theoretically calculated the hh-lh mixing in the QW due to the nearby QD strain and evaluated the PLE ratio Ie-lh/Ie-hh.

Pressure-Induced Bandgap Engineering and Photoresponse Enhancing of Wurtzite CuInS2 Nanocrystals

Nanoscale ◽  
2022 ◽  
Author(s):  
Meiyan Ye ◽  
Yan Li ◽  
Ruilian Tang ◽  
Siyu Liu ◽  
Shuailing Ma ◽  
...  
Keyword(s):  
Optical Properties ◽  
Good Stability ◽  
Effective Strategy ◽  
Bandgap Engineering ◽  
Photoelectrical Properties ◽  
Optoelectronic Applications ◽  
Cuins2 Nanocrystals

Wurtzite CuInS2 exhibits great potential for optoelectronic applications because of its excellent optical properties and good stability. However, exploring effective strategy to simultaneously optimaze its optical and photoelectrical properties remains...

Tailoring the optical properties of tin oxide thin films via gamma irradiation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ateyyah M. Al-Baradi ◽  
Ahmed A. Atta ◽  
Ali Badawi ◽  
Saud A. Algarni ◽  
Abdulraheem S. A. Almalki ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
Gamma Irradiation ◽  
Tin Oxide ◽  
Free Charge Carrier ◽  
Oxide Thin Films ◽  
Dispersion Parameters ◽  
Absorption Spectrum Fitting ◽  
Spectrum Fitting

Abstract In the current work, the optical properties of tin oxide thin films have been tailored via gamma irradiation for energy applications. The effect of Gamma radiation (50, 100, 150, 200 and 250 kGy) on the microstructural, absorption and oscillator parameters of SnO2 thin films has been investigated. XRD results reveal that the SnO2 films have the symmetry of the space group P42/mnm belonging to the tetragonal system. The crystallite size of γ-irradiated SnO2 thin film slightly increases as the irradiation dose increases. The allowed optical band gaps are estimated by applying various methods such as Tauc’s method, derivation of absorption spectrum fitting and absorption spectrum fitting approaches. The dispersion parameters are extracted from the dispersion curve of the real part of the refractive index. The single-effective-oscillator and Drude models for free charge carrier absorption are applied to obtain the dispersion parameters before and after γ-irradiation.

POLARIZATION PROPERTIES OF SYNCHROTRON RADIATION IN THE STUDY OF ANISOTROPIC INSULATING CRYSTALS

2002 ◽  
Vol 09 (01) ◽  
pp. 469-472
Author(s):  
V. N. KOLOBANOV ◽  
I. A. KAMENSKIKH ◽  
V. V. MIKHAILIN ◽  
I. N. SHPINKOV ◽  
D. A. SPASSKY ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Energy Transfer ◽  
Synchrotron Radiation ◽  
Valence Band ◽  
Conduction Band ◽  
Electronic States ◽  
Absorption Region ◽  
New Information ◽  
Fundamental Absorption Region

The optical properties of a wide series of the tungstates with the scheelite and wolframite crystal structure at the threshold of the fundamental absorption region were studied. New information about the influence of the electronic states forming the bottom of the conduction band and the top of the valence band on the formation of emission centers and mechanisms of energy transfer to these centers was obtained.

Influence of Pressure on Structural, Optical and Electronic Properties of As-ZnO

2019 ◽  
Vol 807 ◽  
pp. 110-114
Author(s):  
Ling Ping Xiao ◽  
Yun Qin Liu ◽  
Li Zeng
Keyword(s):  
Optical Properties ◽  
Valence Band ◽  
Density Functional ◽  
Optical Constants ◽  
First Principles Calculations ◽  
Band Shift ◽  
Functional Theory ◽  
Electron Charge Density ◽  
Optical And Electronic Properties ◽  
Doped Zno

First-principles calculations are performed to study the electronic structures and optical properties of the As-doped ZnO under pressure up to 8 GPa. After doped, the electron density difference demonstrates the considerable electron charge density redistribution, which induces the effect of As-doped ZnO to increase the charge overlap between atoms. Moreover, as the pressure increases, the conduction and valence band shift to lower and higher energies, respectively. The shifts of the conduction and valence band result in a decreasing band gap. Additionally, the calculated optical constants of As-doped ZnO under pressure are also presented. Keywords: high pressure; As-doped ZnO; optical properties, Density functional theory.

SPECTROSCOPIC ELLIPSOMETRY INVESTIGATION ON OPTICAL PROPERTIES OF Fe:SNO2 THIN FILMS: EFFECTS OF IRON CONCENTRATION

2020 ◽  
pp. 2050044
Author(s):  
SAHAR MORADI ◽  
HASSAN SEDGHI
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Sol Gel ◽  
Iron Concentration ◽  
Dielectric Constants ◽  
Bandgap Energy ◽  
Dispersion Parameters ◽  
Glass Substrates ◽  
Coating Method

Nanostructured Fe:SnO2 thin films were deposited on glass substrates through sol–gel spin coating method. Films were synthesized with different iron quantities including 0%, 4%, 8% and 12% (wt.%). The effects of Fe concentration on optical properties of films were investigated by spectroscopic ellipsometry (SE) technique. SE measured ([Formula: see text]) parameters for films in the wavelength range between 300[Formula: see text]nm to 800[Formula: see text]nm. Optical properties including the refractive index, extinction coefficient, transmittance, dielectric constants and optical conductivity were determined by fitting the SE measured ([Formula: see text]) parameters and data obtained from the optical model-based analysis. Results showed that the transmittance values increase by increment of Fe concentration from 0% to 12%. The bandgap energy ([Formula: see text] of prepared thin films was also calculated. [Formula: see text] values were between 3.44 and 3.58[Formula: see text]eV. Dispersion parameters including the high frequency dielectric constant ([Formula: see text] and the ratio of free carrier concentration to effective mass (N/m[Formula: see text] were then obtained for the prepared films.

The optical properties and chemical decomposition of lead iodide

1964 ◽  
Vol 280 (1383) ◽  
pp. 566-585 ◽  
Keyword(s):  
Optical Properties ◽  
Absorption Spectrum ◽  
Valence Band ◽  
Conduction Band ◽  
Electron Irradiation ◽  
Irradiation Damage ◽  
Lead Iodide ◽  
Chemical Decomposition ◽  
Excitation Processes ◽  
Split Valence

The optical properties of lead iodide have been measured and the fundamental absorption spectrum is interpreted in terms of ionization and excitation processes. These processes may be regarded as transitions from a split valence band to the conduction band and to exciton levels lying above and below the minimum of the conduction band. This inter­pretation is supported by measurements of photoconductivity and photodecomposition. Two mechanisms are suggested to explain the occurrence of photodecomposition and electron irradiation damage in this substance.

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