Search results for "alum"

Redzamā un infrasarkanā luminiscence alumīnija nitrīda materiālos

2022

Luminiscenti materiāli tiek plaši izmantoti dažādu sensoru un optisko ierīču izgatavošanā. Lai izvērtētu luminoforu piemērotību konkrētiem pielietojumiem, ir nepieciešams apjaust tajos notiekošos luminiscences procesus. Šī maģistra darba ietvaros tika pētīti ar mangānu, eiropiju un hromu aktivētu alumīnija nitrīda (AlN) materiālu luminiscences mehānismi. Tika veikti materiālu rentgendifrakcijas, kā arī luminiscences, tās ierosmes un kinētiku mērījumi. No pētītajām vielām ar visintensīvāko aktivātora luminiscenci izcēlās AlN:Mn. Tam tika novērota arī ilga luminiscence pēc ierosinājuma pārtraukšanas – ilgspīde. Šī darba rezultāti var tikt tālāk izmantoti jaunu luminiscentu materiālu un ierīču…

Electrochemical Fabrication of High K Niobium-Tantalum Mixed Oxides/Poly 3-4 Ethylene Dioxythiophene Junctions.

2012

Sintesi per via elettrochimica di nanowires di leghe Co-Sn

2008

ELECTROCHEMICAL FABRICATION OF METAL/OXIDE/CONDUCTING POLYMER JUNCTIONS FOR ELECTRONIC DEVICES

2014

An impedance study of complex Al/Cu-Al2O3electrode

2011

Electrochemical impedance spectroscopy (EIS) was used to investigate different Cu deposition regimes on Al surface obtained by internal electrolysis and to characterize properties of fabricated electrodes. EIS experimental data confirmed that Cu deposition by internal electrolysis is realized and the complex electrode system is obtained. The main difficulty in preparation of Al/Cu electrodes is to prevent aluminium oxidation before and during electrochemical deposition of Cu particles. In this work NaCl, CH3COONa, K2SO4, mono- and diammonium citrate electrolytes were examined to determine their suitability for impedance measurements. Al/Cu-Al2O3 electrode composition was approved by equival…

The effect of hydration layers on the anodic growth and on the dielectric properties of Al2O3 for electrolytic capacitors

2014

Hydrous films were grown on high purity and cubicity Al foils for electrolytic capacitors in deionized water, ethylene glycol - deionized water and in glycerol - deionized water for different immersion times. According to the X-ray diffraction patterns the hydration treatment allowed to grow a pseudo boehmite layer on Al surface whose morphology is appreciably affected by the bath composition. Capacitance measurements and photoelectrochemical findings suggest that a more compact barrier layer forms during the immersion in alcohol containing solutions. The hydration in water allowed to save energy and to prepare more blocking oxide films. The beneficial effect of hydration in hot water on th…

A molecular electron density theory study of the Lewis acid–catalyzed decomposition reaction of nitroethyl benzoate using aluminum derivatives

2019

Residual strain effects on the two-dimensional electron gas concentration of AlGaN/GaN heterostructures

2001

Ga-face AlGaN/GaN heterostructures with different sheet carrier concentrations have been studied by photoluminescence and Raman spectroscopy. Compared to bulk GaN, an energy shift of the excitonic emission lines towards higher energies was observed, indicating the presence of residual compressive strain in the GaN layer. This strain was confirmed by the shift of the E2 Raman line, from which biaxial compressive stresses ranging between 0.34 and 1.7 GPa were deduced. The spontaneous and piezoelectric polarizations for each layer of the heterostructures have been also calculated. The analysis of these quantities clarified the influence of the residual stress on the sheet electron concentratio…

Measurement of drift mobilities in amorphous organic films using the Time of Flight method

2004

We apply the Time of Flight (TOF) technique to study carrier mobility in N, N’-diphenyl-N,N’-bis(3-methylphenyl) -1,1-biphenyl-4,4’-diamine (TPD) and tris(8-hydroxyquinolato) aluminium (Alq 3 ). These materials are two examples of, respectively, hole and electron transporting molecular materials. Measurements are performed in free air or under vacuum varying the experimental parameters such as laser pulse intensity and single shot irradiation. We observe a transition from dispersive to non dispersive transport changing the experimental conditions.

Photosensitivity of SiO2–Al and SiO2–Na glasses under ArF (193 nm) laser

2009

Abstract Photosensitivity of SiO 2 –Al and SiO 2 –Na glass samples was probed by means of the induced optical absorption and luminescence as well as by electron spin-resonance (ESR) after irradiation with excimer-laser photons (ArF, 193 nm). Permanent visible darkening in the case of SiO 2 –Al and transient, life time about one hour, visible darkening in the case of SiO 2 –Na was found under irradiation at 290 K. No darkening was observed at 80 K for either kind of material. This investigation is dedicated to revealing the electronic processes responsible for photosensitivity at 290 and 80 K. The photosensitivity of both materials is related to impurity defects excited directly in the case …