Unravelling the secrets of the resistance of GaN to strongly ionising radiation

Abstract

GaN is the most promising upgrade to the traditional Si-based radiation-hard technologies. However, the underlying mechanisms driving its resistance are unclear, especially for strongly ionising radiation. Here, we use swift heavy ions to show that a strong recrystallisation effect induced by the ions is the key mechanism behind the observed resistance. We use atomistic simulations to examine and predict the damage evolution. These show that the recrystallisation lowers the expected damage levels significantly and has strong implications when studying high fluences for which numerous overlaps occur. Moreover, the simulations reveal structures such as point and extended defects, density gradients and voids with excellent agreement between simulation and experiment. We expect that the developed modelling scheme will contribute to improving the design and test of future radiation-resistant GaN-based devices.

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

“…The formation of dislocations in GaN irradiated with Xe SHI in this range of energies agrees with MD simulations. 43 The RBS/C analysis not only confirms the m-Raman discussion but also quantifies the damage created in the InGaN/GaN MQWs. However, RBS/C does not give information about the lateral distribution of the defects; it only provides their average concentration at a given depth.…”

“…Indeed, increased damage at the surface was found to a depth of 5 and 18 nm for energies of 45 and 70 MeV, respectively. 43 Slightly higher defect levels are seen for the In signal compared to the Ga signal from the deeper region of the MQWs, suggesting that the InGaN MQWs suffer higher damage than the GaN barriers. Similar results were observed for low energy ion implantation in InGaN/GaN MQWs.…”

Self-powered proton detectors based on GaN core–shell p–n microwires

“…[1][2][3][4][5] Among the wide bandgap semiconductors, GaN is well known for its high resistance to ionizing radiation owed, among other properties, to the large displacement energies of its atoms in the crystal lattice (109 eV for N and 45 eV for Ga) 6 and strong dynamic annealing effects, wherefore it is a strong candidate to be used as material for ionizing radiation detectors. [7][8][9][10][11][12][13] The range of radiation to which GaN is sensitive is extensive 14 and recently GaN has been used to develop self-powered UV and X-ray detectors. [15][16][17][18] Development of growth techniques for GaN also led to fabrication of high quality 1D structures, such as nano-and microwires.…”

Modeling Time‐Resolved Kinetics in Solids Induced by Extreme Electronic Excitation

“…Since the behavior of electrons and holes is different, these sources of energy transfer to the atomic system cannot be reliably traced with a single equation for the electronic system such as the thermodiffusion equation used in TTM–MD. [ 31,33,83 ]…”

“…[31] It is also more complicated to apply TTM-MD to nonmetallic targets. [30,32,33] In contrast to TTM, Monte Carlo modeling is fully capable of tracing nonequilibrium and ballistic electronic transport, effects of valence holes in nonmetallic materials, core holes kinetics, transport of photons, and it does not require fitting parameters. [34] A similar idea for a concurrent MC-MD scheme was previously used in a few codes, such as, e.g., MBN Explorer, [35] XTANT, [36,37] and XMDYN.…”