nshuang Chu

Observation of strong red photoluminescence with broadband in indium oxynitride nanoparticles

Indium oxynitride nanoparticles were synthesized on a silicon substrate in nitrogen atmosphere using the method involving thermal evaporation of pure indium in a two-zone reactor. Nanoscale compositional analysis by energy dispersion spectrum showed the existence of indium oxynitride compound. X-ray diffraction analysis further confirmed high crystallization and nitrogen atom existence within the nanoparticles. Scanning electron microscopy investigations showed shape transformation from amorphous sphere to well-shaped octahedron with an average nanoparticle size ranging from 50nmto1μm when the growth temperature of the substrate was increased from 600to900°C. Photoluminescence study was performed on the indium oxynitride nanoparticle samples grown at different temperatures. It was found that with increasing growth temperatures there was not only the formation of high quality indium oxynitride nanoparticles but also an increase in the intensities of emissions. These nanoparticles grown at 900°C could emit ...

Synthesis of In2O3 nanocrystal chains and annealing effect on their optical properties

The authors reported the synthesis of indium oxide nanocrystal chains on silicon substrates using gold nanoparticles as catalyst on native silicon dioxide. Scanning electron microscopy investigations showed that In2O3 nanocrystal chains were formed. The nanocrystal chains comprised many well shaped octahedron nanoparticles with their size ranging from 20to100nm connected with each other to form a network. Both high resolution transmission electron microscopy and diffraction pattern revealed that the In2O3 nanocrystal chains were single crystalline grown along the [111] direction. Photoluminescence study of In2O3 nanocrystal chains exhibited main photoemission at 544nm due to the recombination between electrons in localized state induced by oxygen vacancies and holes in valence band. After the annealing treatment, the main photoluminescence peak not only slightly redshifted to 558nm but also became narrower, which was attributed to the total localized state away from the conduction band caused by less defe...

UVA light-emitting diode grown on Si substrate with enhanced electron and hole injections

In this work, III-nitride based ∼370  nm UVA light-emitting diodes (LEDs) grown on Si substrates are demonstrated. We also reveal the impact of the AlN composition in the AlGaN quantum barrier on the carrier injection for the studied LEDs. We find that, by properly increasing the AlN composition, both the electron and hole concentrations in the multiple quantum wells (MQWs) are enhanced. We attribute the increased electron concentration to the better electron confinement within the MQW region when increasing the AlN composition for the AlGaN barrier. The improved hole concentration in the MQW region is ascribed to the reduced hole blocking effect by the p-type electron blocking layer (p-EBL). This is enabled by the reduced density of the polarization-induced positive charges at the AlGaN last quantum barrier (LB)/p-EBL interface, which correspondingly suppresses the hole depletion at the AlGaN LB/p-EBL interface and decreases the valence band barrier height for the p-EBL. As a result, the optical power is improved.