Ion damage buildup and amorphization processes in GaAs–Al<i>x</i>Ga1−<i>x</i>As multilayers

Tan, Hark Hoe; Jagadish, Chennupati; Williams, James S.; Zou, Jin; Cockayne, D.J.H.

doi:10.1063/1.363186

Cited by 15 publications

(4 citation statements)

References 34 publications

(52 reference statements)

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“…The damage peak at about 0.25 ps is roughly 10 times higher for PF 4 and 7 times higher for PF 2 than the final damage after the cascade has cooled down. This recombination value (∼10) is 2-3 times higher than in Si [21] and GaAs [105] but much less than in metals; for instance in Fe typical values are ∼50 [106]. There is a second peak in case of PF 4 and Ag projectiles (Figure 6.2).…”

Section: Comparative Study Of Atomic and Molecular Projectilesmentioning

confidence: 91%

Atomistic simulation of damage production by atomic and molecular ion irradiation in GaN

Ullah

Kuronen

Nordlund

et al. 2012

Journal of Applied Physics

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Gallium nitride (GaN) has emerged as one of the most important semiconductors in modern technology. GaN-based device technology was mainly pushed forward by invention of p-type doping and the successful fabrication of light emitting diodes (LEDs) and laser diodes (LDs). Intensive studies in the last 20 years on GaN have significantly advanced the understanding of the properties and have expanded the range of practical applications. Beside basic lighting, current applications of GaN include high-power and high temperature electronics, microwave, optoelectronic devices, and so on.The successful production of optical devices demands efficient tuning of charge carrier lifetime where defect engineering plays a vital role. During growth, varying the level of recombination centers is difficult, whereas ion irradiation can do this job efficiently on a final product. On the other hand, during doping, undesirable defects can also be produced and epitaxial GaN is known to have a highly defective structure. Thus, having both positive and negative aspects, it is very important to have a detailed understanding of irradiation-induced defects.To explain experimental findings, atomic level understanding is necessary, but it is not always possible to have an atomistic view of defect dynamics in experiments. Some damage build-up studies by single ions have been reported in the literature, but not many by molecular ions. In this thesis, the irradiation of GaN by single and molecular ions by the means of atomistic simulations was studied. The irradiation response of both bulk and nano-structured GaN system were studied. For bulk studies, all projectiles were irradiated having the same energy per mass. The damage by molecular ions showed strong dynamic annealing. No non-linearity had been observed in the total number of point defects between single and molecular ions. On the other hand, molecular ions produce larger clusters of point defects than single ions. These large defect clusters can be one of the mechanisms of the experimentally observed faster carrier decay time for molecular projectiles. Defects were mostly concentrated at the surface and near-surface regions, which is also evident from experiments.ii Comparison between a similar mass single ion and a molecular ion show that a single ion produced more defect clusters than molecular ions. This suggests that heavy ions are even more efficient than similar mass cluster ions to quench the carrier lifetime.

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Section: Comparative Study Of Atomic and Molecular Projectilesmentioning

confidence: 91%

Atomistic simulation of damage production by atomic and molecular ion irradiation in GaN

Ullah

Kuronen

Nordlund

et al. 2012

Journal of Applied Physics

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“…Interaction between irradiation-induced point defects may cause their annihilation and removal along interfaces and/or surfaces that function as a sink [16]. One should note that AlGaAs has shown a strong dynamic annealing effect, which protects the adjacent GaAs region from ion damages [50]. However for our GaAs/AlGaAs core-shell NWs, the dynamic annealing effect of the AlGaAs shell may not be as significant due to the small thickness (20-70 nm) [33,51].…”

Section: Discussionmentioning

confidence: 97%

Enhancement of radiation tolerance in GaAs/AlGaAs core–shell and InP nanowires

Xie

Gao

et al. 2018

Nanotechnology

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Radiation effects on semiconductor nanowires (NWs) have attracted the attention of the research community due to their potential applications in space and atomic fields. The effective implementation of NW devices in a radiation environment is a matter of concern. Here, the photoluminescence (PL) and time-resolved PL (TRPL) measurements were performed on both GaAs and InP NWs at room temperature before and after 1 MeV H irradiation with fluences ranging from 1 × 10 to 5 × 10 p cm. It is found that the degradation of lifetime is size-dependent, and typically the minority carrier lifetime damage coefficient is closely correlated with the material and NW diameter. Compared to GaAs and InP bulk material counterparts, the lifetime damage coefficient of NWs decreases by a factor of about one order of magnitude. After irradiation, GaAs NWs with a smaller diameter show a much lower lifetime damage coefficient while InP NWs show an increase in carrier radiative lifetime. The increased size-dependent radiation hardness is mainly attributed to the defect sink effect and/or the improvement of a room temperature dynamic annealing mechanism of the NWs. The InP NWs also showed higher radiation tolerance than GaAs NWs.

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“…Hence, there should be further experiments to investigate NWs with diameter down to a few nanometers. One point that should be noted is that previous study has found defect density to be higher in GaAs than AlGaAs [56] due to enhanced dynamic annealing in the latter. This dynamic annealing could even be more efficient at the interface of GaAs-AlGaAs.…”

Section: Ion Irradiation Effect On Horizontally Dispersed Nw Plmentioning

confidence: 92%

Radiation effects on GaAs/AlGaAs core/shell ensemble nanowires and nanowire infrared photodetectors

Li¹,

Li²,

Tan³

et al. 2017

Nanotechnology

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With the recent advances in nanowire (NW) growth and fabrication, there has been rapid development and application of GaAs NWs in optoelectronics. It is also of importance to study the radiation tolerance of optoelectronic nano-devices for atomic energy and space-based applications. Here, photoluminescence (PL) and time-resolved photoluminescence measurements were carried out on GaAs/AlGaAs core/shell NWs at room temperature before and after 1 MeV proton irradiation with fluences ranging from 1.0 × 10-3.0 × 10 cm. It is found that the GaAs/AlGaAs core/shell NWs with smaller diameter show much less PL degradation compared with the ones with larger diameters. The increased radiation hardness is mainly attributed to the improvement of a room temperature dynamic-annealing mechanism near the surface of the NWs. We also found that the minority carrier lifetime is closely related to both the PL intensity and defect density induced by irradiation. Finally, GaAs/AlGaAs ensemble NW photodetectors operating in the near-infrared spectral regime have been demonstrated. The influence of proton irradiation on light and dark current characteristics also indicates that NW structures are a good potential candidate for radiation harsh-environment applications.

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Ion damage buildup and amorphization processes in GaAs–AlxGa1−xAs multilayers

Cited by 15 publications

References 34 publications

Atomistic simulation of damage production by atomic and molecular ion irradiation in GaN

Atomistic simulation of damage production by atomic and molecular ion irradiation in GaN

Enhancement of radiation tolerance in GaAs/AlGaAs core–shell and InP nanowires

Radiation effects on GaAs/AlGaAs core/shell ensemble nanowires and nanowire infrared photodetectors

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