Carrier localization of as-grown n-type gallium nitride under large hydrostatic pressure.

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...

Carrier Localization in Gallium Nitride

In wide bandgap GaN a large number of interesting and important scientific questions remain to be answered. For example, the large free electron concentration reaching 1019 to 1020 cm-3 in nominally undoped material are ascribed to intrinsic defects because no chemical impurity has been found at such high concentrations. According to theoretical models a nitrogen vacancy acts as a donor but its...

Green Method for Synthesizing Gallium Nitride Nanostructures at Low Temperature

Gallium nitride (GaN) nanostructures (NS) were synthesized using pulseddirect current plasma enhanced chemical vapor deposition (PDC-PECVD) on quartzsubstrate at low temperature (600°C). Gallium metal (Ga) and nitrogen (N) plasma wereused as precursors. The morphology and structure of the grown GaN NS werecharacterized by field emission scanning electron microscope (FE-SEM), transmissionelectro...

Strongly localized excitons in gallium nitride

We report on strong excitonic luminescence in wurtzite GaN at 3.309 and 3.365 eV ~T56 K!. These lines lie well below the band gap and are found commonly in layers grown by different techniques and on different substrates. From detailed photoluminescence investigations we find small thermal activation energies and a very weak electron–phonon coupling. The photoluminescence behavior under hydrost...

Current versus voltage characteristics of GaN/AlGaN/GaN double heterostructures with varying AlGaN thickness and composition under hydrostatic pressure