A study of the structural properties of GaN implanted by various rare-earth ions

Eu-Doped AlGaN/GaN Superlattice-Based Diode Structure for Red Lighting: Excitation Mechanisms and Active Sites

“…It is worth mentioning that the as-grown and HTHP samples were not included since they exhibit a strong photoluminescence under the incidence of the 325 nm He–Cd laser line, which prevented the observation of the phonon modes system. Figure a shows that the Raman spectra of as-implanted samples exhibit: (i) the Brillouin zone (BZ) center phonon lines E 2 h and A 1 (LO), whose intensities decrease and broadenings increase with the Eu fluence and (ii) disorder-activated Raman scattering lines (∼300 and ∼676 cm –1 indicated by asterisks), as reported in refs and . Indeed, it is known that ion implantation increases the defect density; , therefore lifting the wavevector conservation of the first order Raman scattering process, which was demonstrated to be closely related to the GaN calculated phonon density of states DOS function, , in good agreement with our results.…”

“…It is known that Raman spectroscopy is extremely sensitive to the damage created by ion implantation and successfully used to study: the structural properties of GaN implanted with various RE ions, HTHP annealing of ion-implanted GaN films, , as well as structural depth profile in ion implanted GaAs and rapid thermal annealing (RTA) impurity-enhanced interdiffusion in GaAs/AlGaAs QWs. , Moreover, in GaN and GaN-related alloys, the phonons were proved to be an efficient tool for monitoring the crystalline quality and strain state. − Figure a shows Raman spectra of the as-implanted samples with both fluences recorded using the 325 nm excitation. It is worth mentioning that the as-grown and HTHP samples were not included since they exhibit a strong photoluminescence under the incidence of the 325 nm He–Cd laser line, which prevented the observation of the phonon modes system.…”

“…■ RESULTS AND DISCUSSION Raman Spectroscopy. It is known that Raman spectroscopy is extremely sensitive to the damage created by ion implantation and successfully used to study: the structural properties of GaN implanted with various RE ions, 30 HTHP annealing of ion-implanted GaN films, 31,32 as well as structural depth profile in ion implanted GaAs 33 and rapid thermal annealing (RTA) impurity-enhanced interdiffusion in GaAs/AlGaAs QWs. 34,35 Moreover, in GaN and GaN-related alloys, the phonons were proved to be an efficient tool for monitoring the crystalline quality and strain state.…”

Ferromagnetic and paramagnetic magnetization of implanted GaN:Ho,Tb,Sm,Tm films

“…The dual method yields a more homogeneous distribution of Tb ions but the number of defects could be increased by a repeated implantation process. This conjecture is supported by the negligible (GaN:Tb 5 Â 10 15 ) 12 and large 4 effects of annealing on the N D =N and XRD data, respectively. The temperature dependence of the PM susceptibility was measured between 2 and 300 K in the field-cooled regime mostly under an applied field of 10 kOe.…”

“…The details of preparation of the GaN:RE films and their description including the disorder densities N D /N for GaN:Tb,Sm layers were reported in the work. 12 The as-prepared layers used in experiments (Table I) are characterized by a implantation energy and fluency and by a total amount N of the implanted RE atoms N per unit of area determined from the Rutherford backscattering (RBS) and the concentration profile obtained by secondary ion mass spectrometry (SIMS).…”