Photoluminescence Excitation Spectroscopy of Carbon-Doped Gallium Nitride

Polarized photoluminescence excitation spectroscopy of single-walled carbon nanotubes.

The polarized photoluminescence excitation spectra of twenty-five single-walled carbon nanotube species are reported. For light polarized along the nanotube axis, the main absorption resonance at E22 shows sidebands attributed to phonon assisted absorption. Sidebands to E11 have a diameter dependent energy and are assigned to excited excitonic states. Along with longitudinal excitations, severa...

Near-field cathodoluminescence studies on n-doped gallium nitride films

Strongly Localized Donor Level in Oxygen Doped Gallium Nitride

A classification in terms of the localization of donor defects in GaN is performed by Raman spectroscopy under large hydrostatic pressure. We observe a significant decrease of the free carrier concentration in highly O doped GaN epitaxial films at a hydrostatic pressure of 22 GPa. This indicates the presence of a strongly localized donor defect at large pressure. Monitoring the phonon plasmon c...

Spectroscopy of competing mechanisms generating stimulated emission in gallium nitride

Two competing recombination mechanisms of stimulated emission in the vicinity of 145 K have been directly observed in the temperature dependence of the optical emission spectra for high-quality, unintentionally doped gallium nitride. Our analysis of the spectra indicates that exciton-exciton scattering is responsible for stimulated emission below 145 K, while at higher temperatures an electron-...

X-ray Photoelectron Spectroscopy of Aluminum Gallium Nitride

Aluminum Gallium Nitride is an exciting new semiconductor that is not yet fully understood. Detailed electrical analysis can be undertaken using cathodoluminescence spectroscopy, and the results correlated to the relative abundance of the aluminum, gallium, and nitrogen, as well as oxygen impurities.