Graphene quantum dots are known to exhibit tunable photoluminescence (PL) through manipulation of edge functionality under various synthesis conditions. Here, we report observation of excitation dependent anomalous m-n type fingerprint PL transition in synthesized amino functionalized graphene quantum dots (5-7 nm). The effect of band-to-band π*-π and interstate to band n-π induced transitions ...

InGaN/GaN multiple quantum well (MQW) light emitting diode (LED) structures with blue and green light emissions have been grown on sapphire substrates by metalorganic chemical vapor deposition. They are investigated by high-resolution X-ray diffraction (HR-XRD), high-resolution transmission electron microscopy (HR-TEM), photoluminescence (PL) and photoluminescence excitation (PLE). HR-XRD showe...

The photoluminescence (PL) and absorption experiments have been performed in GaSe slab with incident light polarized perpendicular to c-axis of sample at 10 K. An obvious energy difference of about 34 meV between exciton absorption peak and PL peak (the highest energy peak) is observed. By studying the temperature dependence of PL and absorption spectra, we attribute it to energy difference bet...

A series of InGaN/GaN multiple quantum wells with different well thicknesses were grown on sapphire by metal organic chemical vapor deposition, and investigated by excitation power density dependent photoluminescence (PL). With increasing excitation power density, the PL peak position showed a blue shift followed by a red shift. It is believed that a screened quantum-confined Stark effect is re...

The piezoelectric ~PZ! effect is demonstrated for the elongated three-dimensional ~In,Ga!As islands grown on a GaAs ~100! substrate. The photoluminescence ~PL! spectrum is studied as a function of excitation intensity. With increasing excitation intensity, a blue shift and a linewidth reduction of the PL peak from the ~In,Ga!As islands are observed. The observed phenomena are attributed to the ...

We have studied the magnetic field 50 T dependence of the photoluminescence PL of self-assembled InAs /GaAs quantum dots as a function of temperature T . As the temperature is raised from 4.2 up to 80 K, thermal redistribution causes the PL to be increasingly dominated by dots with a lower PL energy. Magneto-PL demonstrates that these low-energy dots are larger in size only in the growth direct...

The bpy, dpe and dppe were introduced as auxiliary ligands, respectively, to construct three magnesium-1,4-NDC coordination polymers (Mg-CPs) that exhibited tunable photoluminescence (PL) and direct white-light emission upon varying the excitation light.

Functionalization of light-emitting poly(3-methylthiophene) (P3MT) nanowires (NWs) with probe-DNA (p-DNA) and their label-free recognition of target-DNA (t-DNA) were correlated quantitatively with both the photoluminescence (PL) color and intensity of P3MT NWs.

We utilized time-integrated and time-resolved photoluminescence of a-axis and c-axis gallium nitride nanowires to elucidate the origin of the blue-shifted ultraviolet photoluminescence in a-axis GaN nanowires relative to c-axis GaN nanowires. We attribute this blue-shifted ultraviolet photoluminescence to emission from surface trap states as opposed to previously proposed causes such as strain ...

The effects of thermal annealing on the emission and microstructural characteristics of GaAs0.88Sb0.10N0.02/InP multiple quantum well (QW) structures were studied by photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). The results show that the optimum annealing conditions lead to improved PL intensity accompanied by only a small blue shift, contrasting the behavior o...