Structural modifications of GaN after cerium implantation

Abstract

Among the family of rare earth (RE) dopants, the doping of first member Ce into GaN is the least studied system. This article reports structure properties of Ce-doped GaN realized by technique of ion implantation. Ce ions were implanted into metal organic chemical vapor deposition grown n-and p-GaN/sapphire thin films at doses 3 Â 10 14 and 2 Â 10 15 cm À2 . X-ray diffraction scans and Raman scattering measurements exhibited expansion of lattice in the implanted portion of the samples. First order Raman scattering spectra show appearance of several disorder-activated Raman scattering modes in addition to typical GaN features. A dose-dependent decrease in intensity of E 2 mode was observed in Raman the spectra of the implanted samples. Ultraviolet Raman spectra of implanted samples show complete quenching of photoluminescence emission and appearance of multiple A 1 (LO) phonon scattering modes up to fifth order. Moreover, a decrease in intensity and an increase in line width of LO modes as a function of wavenumber were observed for implanted samples.

The effects of oxygen co‐doping on structural, magnetic and optical properties of Mn‐doped GaN

“…The clear features at about 562 and 721 cm −1 can be attributed to the E 2 H and A 1 (LO) phonon modes of GaMnN. Comparing to the hexagonal bulk crystal GaN (E 2 H ‐567.8 cm −1 and A 1 (LO)‐735 cm −1 ), the E 2 H peak of the GaMnN films slightly shifts to the low frequency, which is due to the stress formed in the annealing process. Moreover, in our samples, the large red shift of the A 1 (LO) peak of GaMnN is due to the small size of the crystal, because the size of crystal is about ten nanometers according to XRD analysis.…”

Resonant Raman scattering study of V, Cr and Co ions implanted into GaN

“…GaN (E g ¼ 3.4 eV at room temperature) is usually observed when measured using 325 nm (3.841 eV) line of He-Cd laser as a source of excitation. 11,12 Under these conditions, incident and scattered photons resonate and a strong PL emission is observed at around 3144-3210 cm À1 due to band-to-band recombination. 11,12 The intensity and position of this UV luminescence depends upon nature of radiative/non-radiative a Physics Department, University of Gujrat, Gujrat, Pakistan.…”

“…If excitation wavelength is close to band-gap of material, Raman spectrum presents a strong photoluminescence signal, enhancement in intensity of LO phonon and its overtones. 11,12 GaN due to its dominating polar character demonstrates strong interactions of free carriers and LO phonons. 13…”

Recent advances in linear and nonlinear Raman spectroscopy. Part VIII

“…Among other effects, a decrease in intensity and an increase in linewidth of longitudinal optical modes as a function of wavenumber were observed for implanted samples. [201] Martina et al carried out a micro-Raman investigation of early-stage silver corrosion products occurring in sulfur containing atmospheres. The experiments highlight micro-Raman spectroscopy as a highly surface-sensitive technique enabling the detection of both adsorbed chemical species and crystalline corrosion products of only several monolayers of thickness.…”

“…used Raman to study structural modifications of GaN after cerium implantation. Among other effects, a decrease in intensity and an increase in linewidth of longitudinal optical modes as a function of wavenumber were observed for implanted samples . Martina et al .…”