Effect of reactive ion etching on the yellow luminescence of GaN

Abstract

Photoluminescence spectra of GaN grown by metalorganic chemical-vapor deposition on sapphire show that by reactive ion etching, the intensity of the yellow luminescence (YL) band decreases compared to that of the as-grown GaN, due to nonradiative recombination at the damage-induced defect centers. The intensity of the YL in dry-etched GaN has been found to be dependent on rf power and postetch annealing. No change in intensity is observed with further etching indicating a uniform spread of yellow emitters in the epilayer which supports the view that point defects like VGa are the origin of the YL.

Photo-enhanced chemical etched GaN LED on silicon substrate

“…This manifests as a high density of deep-gap donor surface-states, which converts the p-type surface of the LED to n-type, in addition creating significant yellow luminescence [21][22][23][24]. If the surface of the LED device is not textured, the generated photons can be trapped and then reabsorbed by total internal reflection.…”

Photoluminescence depth‐profiling of lattice‐mismatched InGaN thick film on GaN using inductively coupled plasma etching

“…3 Results and discussion The dominant transition peak for In 0.10 Ga 0.90 N, a near-band-edge emission (NBE), was located at a wavelength of about 410 nm (3.03 eV) and a weak bound excitonic peak from the underlying GaN at 363.5 nm (3.41 eV) [6] was also observed in all of the samples, indicating that the InGaN film is homogeneous, free from the InN-rich phase. However, after exposure of the sample to the Cl 2 plasma for 30 sec, the intensity of the peak from InGaN was substantially decreased and the peak from the GaN was increased, as shown in Fig.…”

“…Some interesting results, such as the evolution of yellow luminescence in GaN by using a photoluminescence (PL) with reactive ion etching method were published in the literatures [5,6] and the thickness dependent optical property of thin InGaN quantum well were also investigated by some researchers [7][8][9]. However, PL depth-profiling study on thick InGaN film on GaN, which is the result of complex driving force, has not been reported to date.…”

“…On the other hand, the optical depth profiling study along with dry-etching method proved to be effective in order to understand the structural and optical properties of materials in the growth direction due to the use of identical sample. Some interesting results, such as the evolution of yellow luminescence in GaN by using a photoluminescence (PL) with reactive ion etching method were published in the literatures [5,6] and the thickness dependent optical property of thin InGaN quantum well were also investigated by some researchers [7][8][9]. However, PL depth-profiling study on thick InGaN film on GaN, which is the result of complex driving force, has not been reported to date.…”

Blue photoluminescence activated by surface states in GaN grown by molecular beam epitaxy

“…4 Variations in PL from GaN related to dry, wet, and photoenhanced wet etching have been reported recently. [5][6][7][8] These were explained by a competition between different channels of recombination due to variation of defect concentration in the bulk near-surface layer caused by etching. In particular, Brown et al 5 attributed the 3.0 eV blue emission, which enhanced considerably after reactiveion etching, to some metastable defect closely connected to the yellow luminescence since the bleaching of the blue transition accompanied the emergence of the yellow.…”