Alternating 2,7- and 3,6-linked carbazole copolymers as wide band gap energy transfer donors

2009 ◽  
Vol 517 (9) ◽  
pp. 2840-2844 ◽  
Author(s):  
David F. Pickup ◽  
Hunan Yi ◽  
Harismah Kun ◽  
Ahmed Iraqi ◽  
Mathew Stevenson ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Band Gap ◽  
Wide Band ◽  
Band Gap Energy ◽  
Wide Band Gap ◽  
Gap Energy

Development of flexible Mg and Ga co-doped ZnO thin films with wide band gap energy and transparent conductive characteristics

2014 ◽  
Vol 585 ◽  
pp. 608-613 ◽  
Author(s):  
Seung Wook Shin ◽  
In Young Kim ◽  
G.V. Kishor ◽  
Yeong Yung Yoo ◽  
Young Baek Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Wide Band ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Wide Band Gap ◽  
Gap Energy ◽  
Doped Zno ◽  
Co Doped

scholarly journals Development of β-Ga2O3 layers growth on sapphire substrates employing modeling of precursors ratio in halide vapor phase epitaxy reactor

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Galia Pozina ◽  
Chih-Wei Hsu ◽  
Natalia Abrikossova ◽  
Mikhail A. Kaliteevski ◽  
Carl Hemmingsson
Keyword(s):  
Band Gap ◽  
Vapor Phase ◽  
Wide Band ◽  
Band Gap Energy ◽  
Vapor Phase Epitaxy ◽  
Structural Quality ◽  
Wide Band Gap ◽  
Vacancy Defects ◽  
Sapphire Substrates ◽  
Efficient Power

AbstractGallium oxide is a promising semiconductor with great potential for efficient power electronics due to its ultra-wide band gap and high breakdown electric field. Optimization of halide vapor phase epitaxy growth of heteroepitaxial $$\upbeta$$ β -Ga2O3 layers is demonstrated using a simulation model to predict the distribution of the ratio of gallium to oxygen precursors inside the reactor chamber. The best structural quality is obtained for layers grown at 825–850 °C and with a III/VI precursor ratio of 0.2. Although the structural and optical properties are similar, the surface morphology is more deteriorated for the $$\upbeta$$ β -Ga2O3 layers grown on 5 degree off-axis sapphire substrates compared to on-axis samples even for optimized process parameters. Cathodoluminescence with a peak at 3.3 eV is typical for unintentionally doped n-type $$\upbeta$$ β -Ga2O3 and shows the appearance of additional emissions in blue and green region at ~ 3.0, ~ 2.8, ~ 2.6 and ~ 2.4 eV, especially when the growth temperatures is lowered to 800–825 °C. Estimation of the band gap energy to ~ 4.65 eV from absorption indicates a high density of vacancy defects.

scholarly journals Synthesis of Serrated GaN Nanowires for Hydrogen Gas Sensors Applications by Plasma-Assisted Vapor Phase Deposition Method

2017 ◽  
Vol 7 (3) ◽  
Author(s):  
Mahdi Gholampour
Keyword(s):  
Band Gap ◽  
Vapor Phase ◽  
Gas Sensors ◽  
Wide Band ◽  
Band Gap Energy ◽  
Hexagonal Structure ◽  
Hydrogen Gas ◽  
Wide Band Gap ◽  
Vapor Phase Deposition ◽  
Hydrogen Gas Sensors

Nowadays, the semiconductor nanowires (NWs) typically used in hydrogen gas sensors. Gallium nitride (GaN) with a wide band gap of 3.4 eV, is one of the best semiconductors for this function. NWs surface roughness have important role in gas sensors performance. In this research, GaN NWs have been synthesized on Si substrate by plasma-assisted vapor phase deposition at different deposition time, without using any catalyst. The precursors were gallium (Ga) metal and nitrogen (N) plasma. The GaN NWs were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy )FE-SEM(, photoluminescence (PL) and Raman Spectroscopy. The results indicate the serrated morphology for hexagonal structure of GaN NWs. The band gap energy of GaN NWs was obtained about 3.41 eV. The Raman results show two Raman active optical phonons at 563 cm-1 and 720 cm-1 due to E2(high) and A1(LO), respectively and indicates a good crystallinity of the NWs with the presence of defects in the crystal lattice.

scholarly journals Ti Alloyed α-Ga2O3: Route towards Wide Band Gap Engineering

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1128
Author(s):  
Armin Barthel ◽  
Joseph Roberts ◽  
Mari Napari ◽  
Martin Frentrup ◽  
Tahmida Huq ◽  
...  
Keyword(s):  
Band Gap ◽  
Wide Band ◽  
Atomic Layer ◽  
Band Gap Energy ◽  
Wide Band Gap ◽  
Band Gap Engineering ◽  
Layer Deposition ◽  
Solar Blind ◽  
High Band

The suitability of Ti as a band gap modifier for α-Ga2O3 was investigated, taking advantage of the isostructural α phases and high band gap difference between Ti2O3 and Ga2O3. Films of (Ti,Ga)2O3 were synthesized by atomic layer deposition on sapphire substrates, and characterized to determine how crystallinity and band gap vary with composition for this alloy. We report the deposition of high quality α-(TixGa1−x)2O3 films with x = 3.7%. For greater compositions the crystalline quality of the films degrades rapidly, where the corundum phase is maintained in films up to x = 5.3%, and films containing greater Ti fractions being amorphous. Over the range of achieved corundum phase films, that is 0% ≤ x ≤ 5.3%, the band gap energy varies by ∼270 meV. The ability to maintain a crystalline phase at low fractions of Ti, accompanied by a modification in band gap, shows promising prospects for band gap engineering and the development of wavelength specific solar-blind photodetectors based on α-Ga2O3.

How Can the Intra-Shell Emissions of Rare Earth and Transition Metal Ions in Thin Films and Nanoparticles Be Stimulated?

2008 ◽  
Vol 140 ◽  
pp. 3-8
Author(s):  
M. Godlewski ◽  
S. Yatsunenko ◽  
A. Opalińska ◽  
Witold Łojkowski
Keyword(s):  
Thin Films ◽  
Energy Transfer ◽  
Rare Earth ◽  
Transition Metal ◽  
Band Gap ◽  
Wide Band ◽  
Transition Metal Ions ◽  
Light Sources ◽  
Wide Band Gap ◽  
New Generation

Nanoparticles of the wide band gap oxides doped with rare earth (RE) ions are prospective materials for application in optoelectronics as phosphors in a new generation of light sources. In this paper the mechanisms of the excitation of efficient 4f-4f intra-shell transitions in RE doped nanoparticles are discussed. These mechanisms either enhance the rate of host to impurity energy transfer or stimulate the intra-shell transitions of RE ions.

Eu3+-activated CaGa2O4 wide band gap (WBG) material for solar blind UV conversion: fluorescence and photo-conductivity performance

2014 ◽  
Vol 2 (37) ◽  
pp. 7918-7926 ◽  
Author(s):  
M. Rai ◽  
S. K. Singh ◽  
K. Mishra ◽  
R. Shankar ◽  
R. K. Srivastava ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Band Gap ◽  
Wide Band ◽  
Defect States ◽  
Energy Bands ◽  
Wide Band Gap ◽  
Schematic Representation ◽  
Solar Blind ◽  
Photo Conductivity

Schematic representation of energy bands/defect states, energy transfer and emission in Na+, Eu3+:CaGa2O4 usable for solar blind UV converter application.

Luminescence of Doped Nanoparticles of Wide Band Gap II-VI Compounds

2007 ◽  
Vol 128 ◽  
pp. 123-134 ◽  
Author(s):  
M. Godlewski ◽  
S. Yatsunenko ◽  
M. Zalewska ◽  
A. Kłonkowski ◽  
Tomas Strachowski ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Rare Earth ◽  
Band Gap ◽  
Light Emission ◽  
Wide Band ◽  
Medical Applications ◽  
Al Doping ◽  
Wide Band Gap ◽  
Free Carriers ◽  
Emission Enhancement

Nanoparticles of wide band gap II-VI compounds doped with transition metal (TM) or rare earth (RE) ions are perspective phosphor materials and fluorescence labels for optoelectronic, biology and medical applications. The efficiency of 3d-3d and 4f-4f intra-shell transitions is shown to be enhanced in TM, RE doped nanoparticles. Two mechanisms of emission enhancement related to spin dependent interactions of free carriers with impurities are discussed. These interactions enhance the TM, RE intra-shell transitions by increasing the rate of host to impurity energy transfer. It is shown also that Al doping increases the intensity of light emission from ZnO nanoparticles.

Sign in / Sign up

Export Citation Format

Share Document