Scanning near-field optical spectroscopy was applied to semipolar ð20 2 1Þ InGaN/GaN quantum wells (QWs) to evaluate spatial homogeneity of QW band gap and its dependence on the growth conditions. In the most uniform QW, photoluminescence (PL) spectra were found to be narrow with small peak wavelength and spectral width variations. A QW grown at reduced temperature showed sub-micrometer size PL...

Carbosilane dendrimers with 2-(2-phenyloxy)benzothiazole groups on the periphery were prepared from the 1(st) to the 7(th) generation. All dendrimers were characterized by (1)H- and (13)C-NMR, elemental analysis, MALDI TOF MS, GPC, and PL (photoluminescence) spectroscopy. Characteristic PDI (Polydisperse Index) values of the peaks corresponding to the respective dendrimers in the GPC data is in...

We studied the optical properties of metalorganic chemical vapour deposited (MOCVD) InGaN/GaN multiple quantum wells (MQW) subjected to nitrogen (N) implantation and post-growth annealing treatments. The optical characterization was carried out by means of temperature and excitation density-dependent steady state photoluminescence (PL) spectroscopy, supplemented by room temperature PL excitatio...

CuInS2 nanostructures were  synthesized  via  a  simple  surfactant-free solvothermal  route.  In  this  synthesis,  thiosemicarbazide  and thioglycolic acid were used as sulfur sources. The effects of different parameters such as type of precursor and time on the morphology and particle  size  of  the  samples  have  been  investigated.  The nanostructures  were  characterized  by  means ...

MoS2 is a highly interesting material, which exhibits a crossover from an indirect band gap in the bulk crystal to a direct gap for single layers. Here, we perform a direct comparison between large-area MoS2 films grown by chemical vapor deposition (CVD) and MoS2 flakes prepared by mechanical exfoliation from mineral bulk crystal. Raman spectroscopy measurements show differences between the in-...

Novel YVO(4):Eu(3+)/YBO(3) core/shell heteronanostructures with different shell ratios (SRs) were successfully prepared by a facile two-step method. X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the heteronanostructures. Photoluminescence (PL) study reveals that PL efficiency of the YVO(4):Eu(3+) nanocrystals (cores) can be im...

By direct absorption spectroscopy and comparison to photoluminescence (PL), we investigate negatively charged excitons in dilute two-dimensional electron systems at temperatures down to T = 40 mK in the regime of the fractional quantum Hall effect. At very low temperatures, for filling factor ν < 1/3, an additional excitation appears in the PL spectrum, between the well-known singlet and triple...

We have investigated atomic intermixing in InxGa1−xAs/InP quantum well (QW) structures induced by proton irradiation using photoluminescence (PL) and time-resolved photoluminescence. Photoluminescence results revealed that energy shift was systematically decreased as irradiation temperature was increased, followed by a broadening of the PL linewidth and reduction of the PL intensity. Time-resol...

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 parti...