in this study un-doped and eu-doped zno nanorods and microrads were fabricated by chemical vapor deposition (cvd) method. the effects of annealing, synthesis temperature and structure on structural and photoluminescence properties of eu-doped zno samples were studied in detail. prepared samples were characterized using x-ray diffraction (xrd), scanning electron microscopy (sem), particle size a...

We report the incorporation of graphene-oxide quantum dots (GOQDs) into films, diluted solutions, and light-emitting diodes (LEDs) as part of a water-soluble derivative of poly(p-phenylene vinylene), or PDV.Li, to investigate their impact on the light-emission properties of this model conjugated polymer. Despite the well-known ability of graphene and graphene oxide to quench the photoluminescen...

Carrier relaxation processes have been investigated in GaAs/AlxGa1−xAs v-groove quantum wires (QWRs) with a large subband separation sDE.46 meVd. Signatures of inhibited carrier relaxation mechanisms are seen in temperature-dependent photoluminescence (PL) and photoluminescence-excitation measurements; we observe strong emission from the first excited state of the QWR below ,50 K. This is attri...

The optical characteristics of an indirect type II transition in a series of size and shape-controlled linear CdTe/CdSe/CdTe heterostructure nanorods was studied by steady state and time resolved photoluminescence spectra. The energy and lifetime of the photoluminescence from the charge-separated band structure can be tuned by the band edges of the nanorods. Our results show a size-dependent tr...

This article reports on the studies of porous GaN prepared by ultra-violet (UV) assisted electrochemical etching in a solution of 4:1:1 HF: CH3OH:H2O2 under illumination of an UV lamp with 500 W power for 10, 25 and 35 minutes. The optical properties of porous GaN sample were compared to the corresponding as grown GaN. Porosity induced photoluminescence (PL) intensity enhancement was found in t...

We report on the unusual behaviors of the optical properties for self-assembled InAs/GaAs quantum dots (QDs) by using photoluminescence (PL) spectroscopy. Distinctive double-emission QD peaks are observed in the PL spectra of the samples grown on high growth-temperature condition. From the excitation power-dependent and temperature-dependent PL measurements, these doubleemission peaks are assoc...

We show that new low-energy photoluminescence (PL) bands can be created in the spectra of semiconducting single-walled carbon nanotubes by intense pulsed excitation. The new bands are attributed to PL from different nominally dark excitons that are "brightened" because of a defect-induced mixing of states with different parity and/or spin. Time-resolved PL studies on single nanotubes reveal a s...

We demonstrate label-free imaging of living cells using a GaInAsP semiconductor imaging plate. The photoluminescence (PL) intensity is changed by immersing the semiconductor wafer in different pH solutions and by depositing charged polyelectrolytes on the wafer. Various observations indicate that this phenomenon arises from the radiative and surface recombination rates modified by the Schottky ...

In this paper, we report a broad investigation of the optical properties of germanium (Ge) quantum-well devices. Our simulations show a significant increase of carrier density in the Ge quantum wells. Photoluminescence (PL) measurements show the enhanced direct-bandgap radiative recombination rates due to the carrier density increase in the Ge quantum wells. Electroluminescence (EL) measurement...

Near-field scanning optical microscopy (NSOM) has been used to investigate the photophysical characteristics of first- to fourth-generation (G1 to G4) light-harvesting dendrimer thin films containing coumarin-343 and coumarin-2 as the core and peripheral chromophores, respectively. Thin film photoluminescence (PL) spectra exhibit a significant red shift in the lower generations (G1, G2, and G3)...