Nanowire structures with high-density interfaces are considered to have higher radiation damage resistance properties compared to conventional bulk structures. In the present work, molecular dynamics (MD) is conducted to investigate the irradiation effects and mechanical response changes of GaAs nanowires (NWs) under heavy-ion irradiation. For this simulation, single-ion damage and high-dose ion injection are used to reveal defect generation and accumulation mechanisms. The presence of surface effects gives an advantage to defects in rapid accumulation but is also the main cause of dynamic annihilation of the surface. Overall, the defects exhibit a particular mechanism of rapid accumulation to saturation. Moreover, for the structural transformation of irradiated GaAs NWs, amorphization is the main mode. The main damage mechanism of NWs is sputtering, which also leads to erosion refinement at high doses. The high flux ions lead to a softening of the mechanical properties, which can be reflected by a reduction in yield strength and Young’s modulus.
The dark signal degradation of the CMOS image sensor (CIS) was induced by neutron radiation, and it was modeled by Geant4, which is a three-dimensional Monte Carlo code. The simplified model of the CIS array was established according to the actual pixel geometry, material, and doping concentration. Nuclear elastic interaction and capture interaction were included in the physical processes, and the displacement damage dose in the space charge region of the pixel was calculated. The mean dark signal and dark signal distribution were modeled using Geant4, and the physical mechanisms were analyzed. The modeling results were in good agreement with the experimental and theoretical results.
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