Observation of Band Gap Energy Fluctuation of Microcrystalline InGaN:Zn

2000 ◽  
Vol 639 ◽  
Author(s):  
Hisashi Kanie ◽  
Kosei Sugimoto ◽  
Hiroaki Okado
Keyword(s):  
Band Gap ◽  
Energy Gap ◽  
State Level ◽  
Band Gap Energy ◽  
The Other ◽  
Photoluminescence Excitation ◽  
Energy Fluctuation ◽  
Gap Energy ◽  
Localized State ◽  
Weak Peak

ABSTRACTThis paper describes a comparison of the optical properties of InGaN:Zn with that of GaN:Zn and InGaN by measuring photoluminescence excitation (PLE) spectra at 77 K. It is well known that MOCVD grown InGaN films tend to have a fluctuation in In concentration which results in a fluctuation of the band gap energy. The PL mechanism in InGaN films has been assigned to the annihilation of an exciton at the potential minima caused by the fluctuated band gap potential. We grew InGaN(:Zn) and GaN:Zn microcrystals emitting intense blue luminescence by a reaction of GaN and In2S3 with NH3 in the range of 850 to 900 °C. The samples grown at various temperatures show two PLE peaks: one weak peak is located around 3.47 eV, which we attribute to the band gap energy, and the other peak around 3.15 eV, which we attributed to the In localized state level. We had proposed an atomic structure of the localized state based on an isoelectronic trap theory. However, it is necessary to estimate the order of potential fluctuation of the grown InGaN microcrystal is small in order to assure the isoelectronic trap theory. PLE spectra of InGaN:Zn were measured and compared with that of GaN:Zn to estimate the degree of energy gap fluctuation. As the shape of a PLE peak of InGaN:Zn at around 3.47 eV was comparable to that of GaN:Zn, we concluded that the isoelectronic trap model holds for the grown InGaN microcrystals.

scholarly journals Determination of the direct band-gap energy of InAlAs matched to InP by photoluminescence excitation spectroscopy

1997 ◽  
Vol 81 (10) ◽  
pp. 6916-6920 ◽  
Author(s):  
P. Roura ◽  
M. López-de Miguel ◽  
A. Cornet ◽  
J. R. Morante
Keyword(s):  
Band Gap ◽  
Band Gap Energy ◽  
Photoluminescence Excitation ◽  
Direct Band Gap ◽  
Gap Energy ◽  
Direct Band

scholarly journals Pressure dependence of the band gap energy for dilute nitride and antimony GaNxSbyAs1−x−y

2020 ◽  
Vol 38 (2) ◽  
pp. 248-252
Author(s):  
Chuan-Zhen Zhao ◽  
He-Yu Ren ◽  
Xiao-Dong Sun ◽  
Sha-Sha Wang ◽  
Ke-Qing Lu
Keyword(s):  
Band Gap ◽  
Pressure Range ◽  
Energy Difference ◽  
Band Gap Energy ◽  
The Other ◽  
Dilute Nitride ◽  
Coupling Interaction ◽  
Gap Energy ◽  
N Level ◽  
Two Factors

AbstractDilute nitride and antimony GaNAsSb alloy can be considered as an alloy formed by adding N and Sb atoms into the host material GaAs. Under this condition, its band gap energy depending on pressure can be divided into two regions. In the low pressure range, the band gap energy is due to two factors. One is the coupling interaction between the N level and the Γ conduction band minimum (CBM) of GaAs. The other one is the coupling interaction between the Sb level and the Γ valence band maximum (VBM) of GaAs. In the high pressure range, the band gap energy depends also on two factors. One is the coupling interaction between the N level and the X CBM of GaAs. The other one is the coupling interaction between the Sb level and the Γ VBM of GaAs. In addition, it has been found that the energy difference between the Γ CBM and the X CBM in GaNAsSb is larger than that in GaAs. It is due to two factors. One is the coupling interaction between the N level and the Γ CBM of GaAs. The other is the coupling interaction between the N level and the X CBM of GaAs.

scholarly journals Band Gap Energy in Silicon

2009 ◽  
Vol 8 (2 and 3) ◽  
Author(s):  
Jeremy Low ◽  
Michael Kreider ◽  
Drew Pulsifer ◽  
Andrew Jones ◽  
Tariq Gilani
Keyword(s):  
Temperature Dependence ◽  
Linear Relationship ◽  
Band Gap ◽  
Energy Gap ◽  
Band Gap Energy ◽  
Constant Current ◽  
Gap Energy ◽  
Temperature Range ◽  
Good Agreement

The band gap energy, Eg in silicon was found by exploiting the linear relationship between the temperature and voltage for the constant current in the temperature range of 275 K to 333 K. Within the precision of our experiment, the results obtained are in good agreement with the known value energy gap in silicon. The temperature dependence of Eg for silicon has also been studied.

Effect of Blending on the Enhancement of Electronic Properties of Biopolymers

2016 ◽  
Vol 13 (10) ◽  
pp. 6800-6802
Author(s):  
Naziha Suliman Alghunaim
Keyword(s):  
Hydrogen Bonding ◽  
Dipole Moment ◽  
Molecular Modeling ◽  
Band Gap ◽  
Electronic Properties ◽  
Band Gap Energy ◽  
The Other ◽  
Total Dipole Moment ◽  
Gap Energy ◽  
Chitosan Blends

Chitosan (Cs), gelatin (Gel) and starch (Str) are blended together to investigate the effect of blending upon the electronic properties of biopolymers. Three blends namely 25%, 50% and 75% of (Cs/Gel) and (Cs/Str) respectively. FTIR were utilized to ensure the occurrence of the proposed blend. The FTIR spectra show the occurrence of hydrogen bonding which indicated that the assigned blend is formed as a result of hydrogen bonding of NH2 and COOH terminals. Electronic properties are indicated with molecular modeling technique at PM6 semiemperical level. Modeling results indicate that, as far as starch and gelatin ratios increased in chitosan blends, the band gap energy is decreased in one hand while the total dipole moment is increased on the other hand.

scholarly journals Impact of Thickness on the Optical Properties of Selenium Thin Films

2021 ◽  
Vol 25 ◽  
Author(s):  
Shiva Udachan ◽  
Narasimha Ayachit ◽  
Lingappa Udachan ◽  
Raghunanda Halembre
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Film Thickness ◽  
Band Gap ◽  
Optical Density ◽  
Energy Gap ◽  
Band Gap Energy ◽  
Primary Objective ◽  
Gap Energy ◽  
The Impact

Objectives: The primary objective of this investigation is to make a systematic study on the impact of thickness on optical properties, such as energy gap, absorption coefficient, optical density etc., for selenium thin films. Understanding of the band gap energy and its influence on film thickness is of utmost importance in acquiring the intended electrical characterization of semiconducting films. Materials and methods: Ultra-purity selenium (99.99 %) was deposited on glass substrates. During deposition, the glass substrate with its holder were rotated with constant speed to have a smooth coating. Results and discussions: The XRD findings indicate that selenium is amorphous in nature. The optical band gap energy is found to be decreasing form (2.3 to 2eV) with the rise of film thickness in interval (200 to 1000 nm). The band gap energy obeys inverse square law with respect to thickness. Conclusion: We have properly grown thin films of Se below the De Broglie wavelength limit by thermal evaporation in vacuum. The optical density varies directly with film thickness. The absorption coefficients were in the interval (0.5 to 4) × 107m-1. The AFM results confirmed that the Se nano-size increases with the increase in thickness. Both the grain boundaries and sub-grain regions are clearly visible in the SEM micrographs

scholarly journals Band Gap Energy in Silicon

2008 ◽  
Vol 7 (1) ◽  
Author(s):  
Jeremy Low ◽  
Michael Kreider ◽  
Drew Pulsifer ◽  
Andrew Jones ◽  
Tariq Gilani
Keyword(s):  
Temperature Dependence ◽  
Linear Relationship ◽  
Band Gap ◽  
Energy Gap ◽  
Band Gap Energy ◽  
Constant Current ◽  
Gap Energy ◽  
Temperature Range ◽  
Good Agreement

The band gap energy Eg in silicon was found by exploiting the linear relationship between the temperature and voltage for the constant current in the temperature range of 275 K to 333 K. Within the precision of our experiment, the results obtained are in good agreement with the known value energy gap in silicon. The temperature dependence of Eg for silicon has also been studied.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

2015 ◽  
Vol 7 (3) ◽  
pp. 1923-1930
Author(s):  
Austine Amukayia Mulama ◽  
Julius Mwakondo Mwabora ◽  
Andrew Odhiambo Oduor ◽  
Cosmas Mulwa Muiva ◽  
Boniface Muthoka ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Optical Transition ◽  
Bulk Material ◽  
Band Gap Energy ◽  
Optical Absorbance ◽  
Gap Energy ◽  
Constituent Elements

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the system’s network.

scholarly journals Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1118
Author(s):  
Ibrahim Mustapha Alibe ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Salisu Nasir ◽  
Ali Mustapha Alibe ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Treatment ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Green Emission ◽  
Band Gap Energy ◽  
Solid State Lighting ◽  
Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

Sign in / Sign up

Export Citation Format

Share Document