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

Abstract

Gallium nitride was irradiated with fullerene projectiles having an electronic stopping power above the threshold required to promote ion track formation. The structural and chemical changes induced by fullerene irradiation were studied through Transmission Electron Microscopy (TEM). High resolution TEM inquiries were performed to identify the structural order along the ion tracks and the strain induced in the lattice neighboring the ion tracks. The TEM investigation pointed out local amorphization inside the whole tracks and High Resolution TEM studies in the track periphery evidence local stress in the wurtzite structure. Chemical investigations were carried out by STEM -Electron Energy Loss Spectroscopy (EELS) to describe the chemical order in the neighboring and inside the ion path. Ga/N stoichiometry is essentially maintained in the track core, whereas an oxidation is detected in the ion track, at the surface. Furthermore, the nitrogen k near-edge fine structure investigation reveals the encapsulation of nitrogen bubbles inside the ion tracks.

Examining Different Regimes of Ionization‐Induced Damage in GaN Through Atomistic Simulations

“…Furthermore, a clear sign of the presence of N 2 within the tracks was observed in GaN samples irradiated with fullerene projectiles using Electron Energy Loss Spectroscopy. [ 44 ] Despite being formed by a different mechanism, N 2 bubbles have also been reported previously in ion‐implantation studies (i.e., ions with much lower energies that affect the crystal predominantly via nuclear interactions). [ 45,46 ] Thus, it is expectable that impacts of SHI with ϵ e above a certain threshold produce N 2 bubbles.…”

Microstructure Evolution in He-Implanted Si at 600 °C Followed by 1000 °C Annealing

“…Figure 4 d confirms many intrinsic defects along the edge of a stacking-fault tetrahedron, and that a highly disordered zone and extrinsic defects formed around it. These lattice defects can produce local strain, which can be characterized by geometric phase analysis (GPA) [ 41 ].…”