Reduced thermal quenching in indium-rich self-organized InGaN/GaN quantum dots

Abstract

CitationElAfandy RT, Ng TK, Cha D, Zhang M, Bhattacharya P, et al. (2012) Differences in optical and structural properties of indium rich (27%), indium gallium nitride (InGaN) self-organized quantum dots (QDs), with red wavelength emission, and the two dimensional underlying wetting layer (WL) are investigated. Temperature dependent micro-photoluminescence (lPL) reveals a decrease in thermal quenching of the QDs integrated intensity compared to that of the WL. This difference in behaviour is due to the 3-D localization of carriers within the QDs preventing them from thermalization to nearby traps causing an increase in the internal quantum efficiency of the device. Excitation power dependent lPL shows a slower increase of the QDs PL signal compared to the WL PL which is believed to be due to the QDs saturation. V C 2012 American Institute of Physics.[http://dx

Photoluminescence Oscillations in LEDs Arise from Cylinder-like Nanostructures Fabricated by a Femtosecond Laser

“…Figure b shows that the calculated spectra I (λ, θ) (red line) using the film thickness and the refractive index mentioned above are in accordance with the PL spectra of the irradiated sample at 73.8 mJ/cm 2 (black line). According to eq , I (λ, θ) includes the interference modulation (green line) shown in Figure b, which is characterized by eqs and , and the undisturbed luminescence spectra B (λ) (blue line), which are expressed by the Gaussian spectrum, are shown in Figure b. where λ is the excited wavelength (λ ∼ 453 nm), θ is the degree between the incident light and the detector (θ ∼ 0°), n (λ) is the Cauchy dispersion formula of GaN, and the refractive index of sapphire is acquired from ref . The fitting results are in good agreement with the measured PL spectra, so this oscillating phenomenon is considered as the Fabry–Pérot interference phenomenon.…”

Abnormal Stranski–Krastanov Mode Growth of Green InGaN Quantum Dots: Morphology, Optical Properties, and Applications in Light-Emitting Devices

“…The spectra consist of two peaks. The one with a shorter wavelength can be attributed to the emission from the InGaN WL, while the other peak with a longer wavelength is attributed to the emission from the InGaN QDs. − For sample B, an extremely intense peak centering around 430 nm together with one longitudinal-optical phonon replica can be observed at relatively low temperatures (LTs) (below 150 K), which is referred to the luminescence of the QWs. The TDPL spectra reveal that carriers can tunnel from the QW into the QDs when the GaN barrier in the nanostructure is sufficiently thin.…”