Selective epitaxial growth of InGaN alloys was performed by metalorganic chemical vapor deposition (MOCVD). Templates consisted of arrays of circular etched holes in a SiO 2 mask layer, with pre-grown GaN hexagonal pyramid structures. The room temperature (300 K) photoluminescence (PL) peak wavelength increased with increasing maskopening spacing for a constant mask-opening diameter. For 5 lm d...

Photoluminescence (PL) from femtosecond-laser-modified regions inside cubic-boron nitride (c-BN) was measured under UV and visible light excitation. Bright PL at the red spectral range was observed, with a typical excited state lifetime of ∼4  ns. Sharp emission lines are consistent with PL of intrinsic vibronic defects linked to the nitrogen vacancy formation (via Frenkel pair) observed earlie...

Raman and Photoluminescence (PL) experiments on correlated metallic La0.7Sr0.3MnO3 have been carried out using different excitation wavelengths as a function of temperature from 15 K to 300 K. Our data suggest a Raman mode centered at 1800 cm and a PL band at 2.2 eV. The intensities of the two peaks decrease with increasing temperature. The Raman mode can be attributed to a plasmon excitation w...

The first far-infrared modulated photoluminescence ~FIRM-PL! measurements in InSb/GaSb quantum dots have been performed. Far-infrared absorption is found to both enhance and suppress the quantum dot PL depending on the FIR intensity. This behavior is attributed to the nonthermal distribution of carriers amongst the quantum dots. The spectral dependence of the FIRM-PL signal measures the energy ...

Photoluminescence (PL) measurements have been performed on the nanocomposites of higher fullerene-coupled porous silicon (PS) nanocrystals. For the C70PS and C76(78)PS nanocomposites, the PL spectra show a pinning wavelength at approximately 565 nm and for the C84PS and C94PS nanosystems the pinning wavelength is at approximately 590 nm. The PL pinning property is closely related to the sorts o...

A simple and efficient technique is described for measuring photoluminescence (PL) maps of carbon nanotubes (NTs) in the extended IR range (1-2.3 mum). It consists of preparing an NT/surfactant/gelatin film and measuring PL spectra using a combination of a tunable Ti-sapphire laser excitation and FTIR detection. This procedure has been applied to a wide range of single- and double-wall NTs unve...

We have studied the origin of strong visible photoluminescence ~PL! in a Ge/porous Si ~PS! structure in terms of infrared spectroscopy and electron spin resonance ~ESR!. Spectral analyses indicate that the enhanced PL cannot arise from both the quantum confinement on Ge nanocrystals embedded in the pores and the chemical compound of Ge, O, and H at the surface of the porous Si formed during Ge ...

In this article, I will discuss the optical properties of SiO2-nanoparticles that we have investigated recently by photoluminescence (PL) spectroscopy. In particular, I will show the blue-shifts of PL, originating from the electron-hole recombination of the self-trapped exciton (STE), observed in smaller-sized SiO2-nanoparticles. To explain the size effect in relating to the STE PL shift, a que...

Time-resolved photoluminescence ~PL! spectra are reported for gas-suspended 1–10 nm diameter SiOx particles formed by laser ablation of Si into 1–10 Torr He and Ar. Three spectral bands ~1.8, 2.5 and 3.2 eV! similar to PL from oxidized porous silicon were measured, but with a pronounced vibronic structure. Particle size and composition were determined with Z-contrast transmission electron micro...

We report investigations of CdS–CdSe–CdS (core–well–shell) nanostructures by photoluminescence (PL) spectroscopy at temperatures between 77 and 300 K. PL intensity measurements show a transition from a pumprate-limited regime at low excitation intensity to the range determined by a spontaneous emission lifetime at a high excitation limit. PL intensity changes as a function of temperature. Also,...