Structural and optical properties of Al x Ga1 − x N/Al y Ga1 − y N multiple quantum wells for deep ultraviolet emission

Abstract

The Al x Ga 1 -x N/Al y Ga 1 -y N multiple quantum well (MQW) structure for deep ultraviolet emission has been grown on sapphire by metal organic chemical vapor deposition (MOCVD). High resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and cathodoluminescence (CL) are used to characterize the structural and optical properties of MQWs, respectively. Clear step flows can be observed in the AFM image indicating a two-dimensional growth model. There are many cracks on the surface of the MQW structure because of the high tensile stress. HRXRD shows multiple satellite peaks to the 2nd order. The HRXRD simulation shows that the MQW period is about 11.5 nm. The emission peak of Al x Ga 1 -x N/Al y Ga 1 -y N MQWs is about 295 nm in the deep ultraviolet region from the CL spectra.

Measurements of jet quenching with semi-inclusive hadron+jet distributions in Au+Au collisions at sNN=200 GeV

“…In p+p collisions, the azimuthal distribution of back-to-back dijet pairs is peaked at ∆φ ∼ π, with initial-state and finalstate radiative processes generating acoplanarity that broadens the ∆φ distribution. In nuclear collisions, additional acoplanarity may be induced by jet interactions in hot QCD matter [25,[27][28][29]67], with magnitude related to the jet transport parameterq [27,29,67]. Acoplanarity from vacuum radiation grows with both jet energy and √ s, so that low energy jets may have greatest sensitivity toq [27,29].…”

“…Suppression of jet yield in central compared to the yield in peripheral collisions with the same jet cone radius R measures the energy transported to angles larger than R. Comparison of recoil jet yield at different R measures medium-induced modification of jet shape (intra-jet broadening [25][26][27]). The distribution of ∆φ measures medium-induced acoplanarity (inter-jet broadening).…”

“…The distribution of ∆φ measures medium-induced acoplanarity (inter-jet broadening). Yield enhancement in the tail of the ∆φ distribution could indicate medium-induced Molière scattering off quasi-particles in the hot QCD medium [25,28]. The acoplanarity distribution of low energy jets is sensitive to q · L , whereq is the jet transport parameter and L is the in-medium path length [29].…”

Some Fluorinated Carbonates as Electrolyte Additives for Li(Ni0.4Mn0.4Co0.2)O2/Graphite Pouch Cells

“…20 DiFEC can be made by reacting fluorine gas with ethylene carbonate or by a replacement reaction with dichloroethylene carbonate. 21 Mitsui et al 20 found that adding 5 wt% DiFEC and 0.5% lithium difluorophosphate to EC:EMC 1:1 electrolyte improved the high temperature cycling performance of LiCoO 2 /graphite cells, cycled between 3.0 and 4.2 V. Linear fluorinated carbonates, such as bis(2,2,2-trifluoroethyl) carbonate (TFEC) and methyl-2,2,2-trifluoroethyl carbonate, have been investigated as flame retardant additives or co-solvents in Li-ion cells. 8,[22][23][24][25] The re-sults of these studies suggested that fluorinated organic carbonates increased electrolyte stability toward charged electrodes at high voltages.…”

Superconductivity at 31 K in the “111”-type iron arsenide superconductor Na 1−x FeAs induced by pressure

“…8. Considering volatility loss of Na in the sintering process, the Na 3 As precursor powder, Fe and As powder were mixed according to mole ratio of Na:Fe:As at sodium site that contribute to generate carriers [9,11].…”