Accueil >
Production scientifique
(322) Production(s) de GIL B.
|
|
Excitation-dependent carrier dynamics in Al-rich AlGaN layers and multiple quantum wells
Auteur(s): Šcajev Patrik, Miasojedovas Saulius, Jarasiunas Kestutis, Hiramatsu Kazumaza, Miyake Hideto, Gil B.
(Article) Publié:
Physica Status Solidi A, vol. 252 p.1043-1049 (2015)
Texte intégral en Openaccess :
Ref HAL: hal-01238741_v1
DOI: 10.1002/pssb.201451479
WoS: WOS:000354267300032
Exporter : BibTex | endNote
5 Citations
Résumé: .The combined temporally, spatially and spectrally‐resolved optical techniques, namely the photoluminescence, light induced transient grating, and differential reflectivity were used for investigation of excitation‐dependent PL efficiency, exciton lifetime, and diffusion coefficient in Si‐doped Al‐rich multiple quantum wells and epilayers at various temperatures. Novel features of carrier recombination and in‐plane diffusion were observed. Low‐excitation radiative lifetime of 1–2 ns was found temperature‐independent in 80–150 K interval, while it sublinearly decreased with excitation at excess carrier densities above 1018 cm−3. The lifetime decrease correlated with the increase of diffusion coefficient, indicating excitation‐enhanced delocalization of localized excitons and therefore enhanced capture to nonradiative centers. The droop of photoluminescence efficiency with excitation was the strongest at 80–150 K due to strong delocalisation at low‐temperatures, while at higher temperatures the thermal activation prevailed in photoluminescence excitation dependence. The photoluminescence efficiency quenching at T > 200 K provided rather high activation energies of ∼100 and 160 meV for Al‐rich multiple quantum wells and epilayers, correspondingly.
|
|
|
Optical properties and structural investigations of (11-22)-oriented GaN/Al0.5Ga0.5N quantum wells grown by molecular beam epitaxy
Auteur(s): Rosales D., Gil B., Bretagnon T., Brault Julien, Vennegues Philippe, Nemoz Maud, de Mierry Philippe, Damilano Benjamin, Massies Jean, Bigenwald Pierre
(Article) Publié:
Journal Of Applied Physics, vol. 118 p.024303 (2015)
|
|
|
Strain-compensated (Ga,In)N/(Al,Ga)N/GaN multiple quantum wells for improved yellow/amber light emission
Auteur(s): Lekhal K., Damilano B., Ngo H. T., Rosales D., de Mierry P., Hussain S., Vennegues P., Gil B.
(Article) Publié:
Applied Physics Letters, vol. 106 p.142101 (2015)
Texte intégral en Openaccess :
|
|
|
Determination of carrier diffusion length in GaN
Auteur(s): Hafiz Shopan, Zhang Fan, Monavarian Morteza, Avrutin Vitaliy, Morkoc Hadis, Oezguer Uemit, Metzner Sebastian, Bertram Frank, Christen Juergen, Gil B.
(Article) Publié:
Journal Of Applied Physics, vol. 117 p.013106 (2015)
|
|
|
Yellow–red emission from (Ga,In)N heterostructures
Auteur(s): Damilano Benjamin, Gil B.
(Article) Publié:
Journal Of Physics D: Applied Physics, vol. 48 p.403001 (2015)
Ref HAL: hal-01206060_v1
DOI: 10.1088/0022-3727/48/40/403001
WoS: 000362006400001
Exporter : BibTex | endNote
72 Citations
Résumé: (Ga,In)N-based light emitting devices are very efficient in producing blue light and to a lesser extent green. Extending their spectral range to longer wavelengths while maintaining high efficiency is a challenge due to material and physical issues related to high-In content (Ga,In) N alloys. We review the current status of yellow and red emitters (light emitting diodes and laser diodes) based on this material system. We also describe the state-of-the-art of devices mixing blue–yellow or red–blue–green coloured light, such as monolithic phosphor-free white light emitting diodes and full-colour micro-displays.
|
|
|
Internal quantum efficiency in yellow-amber light emitting AlGaN-InGaN-GaN heterostructures
Auteur(s): Ngo T. H., Gil B., Valvin P., Damilano B., Lekhal Kaddour, de Miery Philippe
(Article) Publié:
Applied Physics Letters, vol. 107 p.122103 (2015)
Ref HAL: hal-01203313_v1
DOI: 10.1063/1.4931624
WoS: 000361832600023
Exporter : BibTex | endNote
28 Citations
Résumé: We determine the internal quantum efficiency of strain-balanced AlGaN-InGaN-GaN hetero-structures designed for yellow-amber light emission, by using a recent model based on the kinetics of the photoluminescence decay initiated by Yoshiya Iwata, Ryan G. Banal, Shuhei Ichikawa, Mitsuru Funato, and Yoichi Kawakami, Journal of Applied Physics 117, 075701 (2015). Our results indicate that low temperature internal quantum efficiencies sit in the 50 % range and we measure that adding an AlGaN layer increases the internal quantum efficiency from 50% up to 57 % with respect to the GaN-InGaN case. More dramatic, it almost doubles from 2.5 % up to 4.3 % at room temperature.
|
|
|
X-ray diffraction study of A- plane non polar InN epilayer grown by MOCVD
Auteur(s): Moret M., Briot O., Gil B.
Conference: GALLIUM NITRIDE MATERIALS AND DEVICES X (San Francisco, US, 2015)
Actes de conférence: Proceedings of SPIE, vol. 9363 p.936328 (2015)
Ref HAL: hal-01134316_v1
DOI: 10.1117/12.2077513
WoS: WOS:000354279300033
Exporter : BibTex | endNote
2 Citations
Résumé: Strong polarisation-induced electric fields in C-plane oriented nitrides semiconductor layers reduce the performance of devices. Eliminating the polarization fields can be achieved by growing nitrides along non polar direction. We have grown non polar A-plane oriented InN on R-plane (1‾102) nitridated sapphire substrate by MOCVD. We have studied the structural anisotropy observed in these layers by analyzing High Resolution XRay Diffraction rocking curve (RC) experiments as a function of the in-plane beam orientation. A-plane InN epilayer have a unique epitaxial relationship on R-Plane sapphire and show a strong structural anisotropy. Full width at half maximum (FWHM) of the InN(11‾20) XRD RC values are contained between 44 and 81 Arcmin. FWHM is smaller when the diffraction occurs along the [0001] and the largest FWHM values, of the (11‾20) RC, are obtained when the diffraction occurs along the [1‾100] in-plane direction. Atomic Force Microscopy imaging revealed morphologies with well organized crystallites. The grains are structured along a unique crystallographic orientation of InN, leading to larger domains in this direction. This structural anisotropy can be, in first approximation, attributed to the difference in the domain sizes observed. XRD reciprocal space mappings (RSM) were performed in asymmetrical configuration on (13‾40) and (2‾202) diffraction plane. RSM are measured with a beam orientation corresponding to a maximal and a minimal width of the (11‾20) Rocking curves, respectively. A simple theoretical model is exposed to interpret the RSM. We concluded that the dominant contribution to the anisotropy is due to the scattering coherence length anisotropy present in our samples. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE)
|