GaAs is a compound semiconductor material with applications such as semiconductor lasers. The study of irradiation effects in materials has in the past been used to obtain information about point defect migration and coalescence processes in materials. This paper reports on the nature of the dislocation loops in GaAs irradiated with neutrons to a fluence of 2.83×10~(20)n/cm~2 (> 0.82MeV), followed by annealing at 900°C for 20 minutes. As far as we know, the nature of dislocation loops in neutron irradiated GaAs has not been determined and reported yet. The dislocation loops in the irradiated and annealed GaAs were analysed using conventional and high resolution transmission electron microscopy (TEM). The irradiation of GaAs by fast neutrons generates point defects (interstitials and vacancies) which will migrate, coalesce or annihilate during annealing when these point defects become mobile. It has been reported earlier that in GaAs irradiated with 1 MeV electrons, small interstitial dislocation loops on {110} planes became visible after annealing at 500°C. Since these dislocation loops act as preferential sinks for interstitials, the loops will grow in size with increasing annealing temperature. In this investigation the neutron irradiated GaAs was annealed at 900°C in order to create loops large enough for analysis.
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