Electrochemical etching of <Emphasis Type="Italic">p–n</Emphasis>-GaN/AlGaN photoelectrodes

Specific features of etching of GaN/AlGaN p–n structures in a KOH-based electrolyte have been studied. It was found that the corrosion process first passes across p layers through vertical channels associated with threading structural defects. Then, the corrosion process occurs in the lateral direction along n layers of the structure, with local hollows and voids thereby formed. The lateral etching is due to the presence of positive piezoelectric charges at boundaries of n-AlGaN and n-GaN layers and positively charged ionized donors in the space-charge region of the p–n junction.     

Studying the Sensitivity of Graphene for Biosensor Applications

Technical Physics Letters - We have studied the response of graphene-film-based chips on SiC substrates (the relative change in the chip resistance) to coming into contact with fluorescein...     

Water-activated photoluminescence of europium(III) β-diketonate complex in a porous glass matrix

Europium(III) β-diketonate complex Eu(DBM)₃ · phen (DBM = dibenzoylmethane, phen = 1,10-phenanthroline) have been encapsulated in a porous glass matrix by impregnating it with an acetone solution of the complex. Subsequent filling of the pore space with water leads to a significant increase in the intensity of photoluminescence from the deposited complex molecules. A key role in the unusual behavior of the system belongs to the coordination environment of Eu³⁺ that ensures screening of these ions from water molecules and increases the efficiency of indirect excitation of emission by increasing the rate of π → π* transitions in the ligand system in the presence of water condensed in the pores.     

Adsorption and Luminescence Properties of Porous Glasses Containing Europium(III) Chloride Nanoparticles

Europium(III) chloride is encapsulated into a porous glass through impregnation with a 0.1 M aqueous solution of the salt with subsequent elimination of water from the pore space. The results of comparing the intercalate content with spatially geometric parameters of the carrier, the increased adsorption of water by a modified glass, and the character of luminescence quenching due to the adsorption of water indicate that the salt particles in the porous glass have nanometer sizes.     

Sensitization of Eu3+ luminescence with titanium(IV) oxide in the composition of nanoparticles in porous glasses

A series of modified porous glasses with a fixed europium content Q(Eu³⁺) = 30 μmol/g and a variable titanium oxide content Q(TiO₂) = 15–375 μmol/g are synthesized. The luminescence properties of the prepared glasses are investigated as a function of the component ratio in the composition of oxide nanoparticles. The specific features of the luminescence quenching in a wet medium are analyzed. It is shown that titanium(IV) oxide substantially sensitizes the photoluminescence of Eu³⁺ ions and shields them against the water adsorption.