Effects of electronic and nuclear stopping power on disorder induced in GaN under swift heavy ion irradiation

Exploring swift-heavy ion irradiation of InGaN/GaN multiple quantum wells for green-emitters: the use of Raman and photoluminescence to assess the irradiation effects on the optical and structural properties

“…As the absorption band at 2.75 eV observed for irradiated MQWs is identical to the one observed for irradiated c-plane GaN layers (Fig. S1 in the ESI †), 26 the Raman spectrum of c-plane GaN layers grown on sapphire and irradiated with 74 MeV Xe SHI was measured under the same experimental conditions (Fig. 3c).…”

“…These bands have been attributed to disorder-activated Raman scattering of the highest acoustic-phonon branch mediated by isolated V Ga , and to other vacancy type defects in the N sublattice, respectively. 26,34,35 The existence of V Ga defects had already been associated with irr-AB observed in the optical transmittance spectra (Fig. 1b).…”

“…Its origin was linked to gallium vacancies (V Ga ) and its concentration was correlated with the number of atomic displacements triggered by nuclear elastic collisions. 26 Computational calculations using density functional theory (DFT) have also predicted that the (2À/3À) charge-state transition level of V Ga occurs at around this energy (2.6-2.8 eV). 27,28 Thus, it is possible to relate irr-AB observed in this work to V Ga induced by Xe SHI irradiation in the GaN lattice.…”

Caractérisation par nanoindentation du GaN irradié par des ions uranium de grande énergie

“…Sa loi de comportement, tout comme l'évolution de son module et de sa dureté, plus stables en fonction de la profondeur de pénétration, rappelle le comportement d'un matériau amorphe. Même s'il aété montré que le GaN après bombardement ionique reste cristallin, les traces latentes créées par le passage des ions lourds peuvent comporter de petites poches de matière amorphes [21][22][23]. Dans un régime de recouvrement des traces, chaque nouvel ion qui traverse apporte une nouvelle partie amorphe, et augmente la fraction de matière amorphe des films, sans toutefois aboutirà la création de zones totalement amorphes [22,23] : la réponse du GaN tend alors vers celle d'un matériau amorphe.…”

Fullerene irradiation leading to track formation enclosing nitrogen bubbles in GaN material

“…In addition, an increase of the electronic stopping power induces latent tracks displaying more continuous morphology/shape [22]. Others studies found that swift heavy ion irradiation on GaN produces disordered tracks and generates lattice stress [24,25]. The impact produced by the projectile exhibits a circular area i.e.…”