Large blueshift and linewidth increase in photoluminescence ~PL! spectra of InAs quantum dots ~QD’s! in n-i-p-i GaAs superlattice were observed. By increasing the excitation intensity from 0.5 to 32 W/cm, the PL peak position blueshifted 18 meV, and the linewidth increased by 20 meV. Such large changes are due to the state-filling effects of the QD’s resulted from the separation of photogenerat...

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...

Photoluminescence (PL) spectra of single nitrogen vacancy (NV) centers in 50-nm diamond nanocrystals at the zero-phonon line (ZPL) were directly observed using a Fabry-Perot interferometer at cryogenic temperatures. The narrowest linewidth of ZPL was 1.2 GHz (1.9 ± 0.7 GHz on average), comparable to ZPL linewidths in PL spectra reported for NV centers in pure bulk diamond. This observation is i...

Nanocrystalline Zinc Oxide (ZnO) powders with different morphology have been successfully synthesized by using different surfactants such as Cetyl Trimethyl Ammonium Bromide (CTAB), Sodium Dodecyl Sulphate (SDS), and Tri Ethanol Amine (TEA) via hydrothermal method. The products were characterized by means of powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electr...

Photoluminescence (PL) dynamics in single-walled carbon nanotubes (SWNTs) has been studied by the femtosecond excitation correlation method with a 150 fs time resolution. The SWNT samples were synthesized by different methods and suspended in gelatin films or D2O solutions. The PL dynamics of SWNTs depends on the local environment surrounding the SWNTs rather than the synthesis methods. The ver...

We have studied the low temperature photoluminescence ~PL! of a d-doped ZnSe:~Te,N! system using two different types of samples, one with single d layers separated by undoped spacers and the other with three adjacent d layers in each doping cycle. We have concluded that both Te and N participate in radiative recombination. We observe a relatively low PL efficiency ~compared to samples without N...

We measured the photoluminescence (PL) spectra of a series of Gen quantum wells as a function of temperature, from 2K to 50K. The PL spectra at 2.1K are dominated by broad emission lines, which can be interpreted as recombination across the indirect gap of the Si/Ge microstructure and are strongly in uenced by the interface morphology of each sample. Beyond T & 15K, all samples show identical s...

Combined interand intra-band spectroscopy studies are presented on structurally well-characterized InAs/GaAs(001) self-assembled quantum dots grown via conventional continuous deposition and the innovative punctuated island growth approach. Temperature and power dependent photoluminescence (PL) and PL Excitation (PLE) on these remarkably uniform quantum dot based samples (with typical PL linewi...

We report a treatment that enhances and stabilizes the photoluminescence (PL) from porous Si films. Films prepared by anodization in a 50% HF/ethanol solution were annealed at 450 “C! in vacuum, exposed to air, and then exposed to a remote-hydrogen plasma. Infrared absorption spectroscopy revealed that the concentration of oxygen, rather than hydrogen, was increased by the processing steps, and...

Reaction order in Bi-doped oxide glasses depends on the optical basicity of the glass host. Red and NIR photoluminescence (PL) bands result from Bi(2+) and Bin clusters, respectively. Very similar centers are present in Bi- and Pb-doped oxide and chalcogenide glasses. Bi-implanted and Bi melt-doped chalcogenide glasses display new PL bands, indicating that new Bi centers are formed. Bi-related ...