Photo-oxidation of densely packed monolayer of CdSe quantum dots ~QDs! was studied by time-resolved photoluminescence ~PL! spectroscopy. Electrons yielded in QDs by the strong laser-pulse irradiation can assist the oxidation of CdSe QDs. Such rapid photo-oxidation does not introduce more nonradiative defects, instead, it enhances the coupling between QDs through surface modification and the PL ...

We fabricated ordered GaAs/AlGaAs quantum dots (QDs) on patterned GaAs(0 0 1) substrates and investigated their optical properties by micro-photoluminescence (m-PL) spectroscopy. Sharp excitonic lines with single photon emission properties were observed. Polarization-dependent PL was performed to resolve the optical fine structure splitting of neutral excitonic lines and to identify the neutral...

The acid oxidation of carbon nanotube generally results in opening the close ends of the nanotube and to make surface modifications. Herewith, Multiwall carbon nanotubes (MWCNTs) were oxidized in acids at high temperature experimental conditions which led to the formation of graphene quantum dots (GQDs).   High resolution transmission electron microscope (HRTEM), energy dispersive X-ray spectro...

Photoluminescence (PL) spectra have been used to elucidate the band structure of graphene oxide (GO) reduced in aqueous solution. The GO reduction is measured in situ via the identification of four PL peaks produced from GO solutions with different concentrations. Using corresponding UV-visible and photoluminescence excitation (PLE) spectroscopy, and on progressing from high energy to low energ...

A new type of large area metal organic chemical vapor deposition (MOCVD) system for the growth of high quality and large size ZnO materials is introduced. Materials properties of the un-doped, nand p-doped ZnO epi-films grown on sapphire substrates by this MOCVD system are studied by various techniques, including high resolution X-ray diffraction (XRD), UV–Visible optical transmission (OT), pho...

In this study, the TiO2 nanorods were synthesized from P25 TiO2 nanoparticles by hydrothermal method in 10 M NaOH solution. The effects of annealing temperatures on produced nanorods were investigated  by scanning  electron microscopy (SEM) X-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. Diameter growth...

in this research calcium fluoride nanoparticles and its different amount of cerium ion dopant (5%and 10%) were prepared. the mentioned nanoparticle were studied by fourier transform infrared spectroscopy (ftir) , x-ray diffraction (xrd), absorption and photoluminescence spectra (pl) and scanning electron microscopy (sem). the xrd patterns indicate a typical cubic fluorite structure and no other...

calcium fluoride nanoparticles with special amount of cerium ion (%1) were synthesized by coprecipitation. fourier transforms infrared spectroscopy (ftir), x-ray diffraction (xrd), absorption and photoluminescence (pl) from caf2ce nanoparticles has been investigated. ftir spectra reveal that there are some amounts of oh, no3 and other organic functional groups on the particle surfaces before th...

Self-assembled organic-inorganic CH3NH3PbI3 perovskite microwires (MWs) upon humidity exposure along several weeks were investigated by photoluminescence (PL) spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). We show that, in addition to the common perovskite decomposition into PbI2 and the formation of a hydrated phase, humidity induced a gradual PL redshift at the initial weeks t...