Yellow and green luminescence in a freestanding GaN template

Carbon defects as sources of the green and yellow luminescence bands in undoped GaN

Gallium vacancies and the yellow luminescence in GaN

We have investigated native defects and native defect-impurity complexes as candidate sources for the yellow luminescence in GaN. Using state-of-the-art first-principles calculations, we find strong evidence that the Ga vacancy (VGa) is responsible. The dependence of the VGa formation energy on Fermi level explains why the yellow luminescence is observed only in n-type GaN. The VGa defect level...

Photoluminescence Study of Gallium Nitride Thin Films Obtained by Infrared Close Space Vapor Transport

Photoluminescence (PL) studies in GaN thin films grown by infrared close space vapor transport (CSVT-IR) in vacuum are presented in this work. The growth of GaN thin films was done on a variety of substrates like silicon, sapphire and fused silica. Room temperature PL spectra of all the GaN films show near band-edge emission (NBE) and a broad blue and green luminescence (BL, GL), which can be s...

Fe-doped AlGaN/GaN HEMTs: Kink-Effect Screening using Yellow Luminescence?

Yellow luminescence (YL) analysis was investigated as a possible route for the screening of as-grown wafers for kink effect in Fe-doped AlGaN/GaN HEMTs, i.e., prior to their final fabrication. This is because the kink effect in the output characteristics of GaN HEMTs has previously been suggested to originate from YL-related defect states. In contrast to earlier works, no direct correlation bet...

Selective excitation of the yellow luminescence of GaN

The yellow luminescence of n-type GaN has been studied with selective excitation using a combination of Ar`-ion and dye lasers. Narrower structures whose peak energies follow the excitation photon energy over the width of the yellow luminescence have been observed. Unlike the yellow luminescence excited by the above band gap excitations, these "ne structures exhibit thermal activated quenching ...