Next Article in Journal
Prediction of Compressive Strength of Fly Ash-Slag Based Geopolymer Paste Based on Multi-Optimized Artificial Neural Network
Previous Article in Journal
Design of Refractory Alloys for Desired Thermal Conductivity via AI-Assisted In-Silico Microstructure Realization
Previous Article in Special Issue
Positron Annihilation Study of RPV Steels Radiation Loaded by Hydrogen Ion Implantation
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:

Application of Proton Irradiation in the Study of Accelerated Radiation Ageing in a GaAs Semiconductor

Institute of Nuclear and Physical Engineering, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology in Bratislava, Ilkovicova 3, 81219 Bratislava, Slovakia
European Organization for Nuclear Research (CERN), 1211 Geneva, Switzerland
Advanced Technologies Research Institute, Faculty of Materials Science and Technology, Slovak University of Technology in Bratislava, Jana Bottu 25, 91724 Trnava, Slovakia
Authors to whom correspondence should be addressed.
Materials 2023, 16(3), 1089;
Received: 21 December 2022 / Revised: 17 January 2023 / Accepted: 21 January 2023 / Published: 27 January 2023


Proton irradiation experiments have been used as a surrogate for studying radiation effects in numerous materials for decades. The abundance and accessibility of proton accelerators make this approach convenient for conducting accelerated radiation ageing studies. However, developing new materials with improved radiation stability requires numerous model materials, test samples, and very effective utilization of the accelerator beam time. Therefore, the question of optimal beam current, or particle flux, is critical and needs to be adequately understood. In this work, we used 5 MeV protons to introduce displacement damage in gallium arsenide samples using a wide range of flux values. Positron annihilation lifetime spectroscopy was used to quantitatively assess the concentration of radiation-induced survived vacancies. The results show that proton fluxes in range between 1011 and 1012 cm−2.s−1 lead to a similar concentration of monovacancies generated in the GaAs semiconductor material, while a further increase in the flux leads to a sharp drop in this concentration.

1. Introduction

In the last several decades, dominated by silicon (Si) and gallium arsenide (GaAs), semiconductors have shaped the new technological era with diodes, transistors, and integrated circuits [1]. Gradually, semiconductor technology has entered all industry areas, including nuclear power production. While the previous generation of nuclear power plants restricted the use of electronic devices to an inevitable minimum, recent nuclear plants rely on the electronics used not just in the digital computers and process control systems in a mild environment, but also in harsh radiation conditions, whereas the use of different electronic systems is not limited to detector technology only.
The application of semiconductors in harsh radiation environments is significantly increasing, not just by nuclear power plants, but also in medical diagnostics, nuclear science, technology, research, and space applications. In all of these fields, high-energy charged particles interact with essential safety and other components, modifying their microstructure and affecting their lifetime. Therefore, the need for safe long-term operation of the semiconductors is crucial for the reliability of electronic instruments, and any failure in critical components leads to substantial economic and human safety hazards in all of these applications.
Despite their susceptibility to permanent degradation and catastrophic failure due to heavy-ion exposure [2], numerous research publications have already pointed out that future semiconductor technologies, including those for space, detectors, medicine, and nuclear applications, consider the application of wide band gap (WBG) semiconductors such as GaN and SiC. In these crystals, the gap between the valence and conduction bands is an essential parameter that defines not only the electrical properties, but also the susceptibility to radiation [3]. The advantage of WBG compared with classical semiconductors such as silicon and gallium arsenide is in the improved electrical properties, such as a higher efficiency, switching frequency, operating temperature, and higher operating voltage [4,5]. This leads to faster, dimension-wise, smaller, more powerful, and more efficient components. These capabilities will be reflected in smaller sizes and weights and will have less power demand due to limited power losses [3,6].
While natural radiation environments, such as the ionosphere, trapped radiation belts, solar particle events, and galactic cosmic rays dominate in outer space, on the ground, various man-made applications lead to the exposure of semiconductor materials to ionizing radiation. Although the understanding of their radiation tolerance is far from complete, silicon carbide (SiC) and gallium nitride (GaN) semiconductors are expected to have superior electrical properties, and their susceptibility to harsh radiation environments compared with the more conventional semiconductors needs to be understood in more detail. It could be expected that because of the improved electrical and radiation properties, GaN has excellent potential to improve a safe long-term operation, decreasing the life-cycle cost and lowering the occurrence of failure, which could lead to personal safety risks. [7,8].
Radiation effects in semiconductor-based electronics due to harsh radiation environments can be divided into two categories, namely the short-term temporary effects and the long-term permanent degradation. The short-term temporary effect comes mainly from the effects of ionising energy loss in the semiconductor by the energetic particle, causing single event effects (SEEs) such as single event upset (SEU), single event transient (SET), single event latch-up (SEL), single event gate rupture (SEGR), or single event burnout (SEB). On the other hand, the long-term effects are dominantly created by the non-ionising energy losses in the material by the displacement damage, where elastic collisions with the material can eject atoms from their standard position in the lattice or when primary recoil atoms collide with other atoms in the lattice [9,10].
While “realistic” low-dose long-term irradiation experiments provide reliable data for assessing the electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation, their potential is significantly decreased for fast technological development due to the time-consuming nature of the approach, which also represents a significant cost in the radiation experiment. To guarantee reliable long-term operation in harsh radiation environments for a reasonable duration of the experiment, semiconductors must undergo suitable accelerated ageing tests. A proper accelerating radiation ageing mechanism is necessary among other ageing mechanisms such as thermal and mechanical vibration, contributing to the successful assessment of the lifetime of electronic devices. However, there has not been an engineering consensus yet on how the results of accelerated ageing experiments can be extrapolated to the engineering and design of technologies for long-term applications. A deep understanding of the evolution of the microstructure exposed to accelerated radiation tests inevitably requires employing both theoretical modelling and suitable experimental characterisation methods sensitive to the atomic-scale lattice defects. This is a very complicated and challenging task due to the limited size sensitivity of the experimental techniques on the one hand, and the limited size of the theoretical calculation models on the other.
For the characterisation of the material damage, a positron annihilation spectroscopy using a 22Na positron source was used. Positron annihilation spectroscopy (PAS) has been used as a microstructural characterisation tool that is sensitive to vacancy-type defects. This technique has been widely used in characterising various types of defects in semiconductors since the 1970s. Positron annihilation experiments were successfully used in the characterisation of radiation effects in (not only) semiconductors modified in numerous types of radiation experiments [11,12], including gamma radiation [13], electron irradiation, and neutron irradiation [14], as well as proton irradiation [15]. In this paper, we used this technique to obtain a quantitative characterisation of the radiation-induced vacancy-type defects, which were investigated as a function of the proton flux (displacement damage rate).
This work aims to explore the feasibility of using proton implantation as a mechanism for the radiation ageing of semiconductors and to improve the understanding of the process of creating displacement damage in bulk GaAs semiconductor material. The particular goal of the study is to describe the role of the “flux effect” on the evolution of the microstructure. In other words, the work was aimed at achieving a better understanding of how to optimise accelerated-ageing irradiation experiments in order to make them a physically meaningful representation of the long-term permanent degradation of the material exposed in the radiation field, so as to establish a comparison between the produced defects and surviving defects in the irradiated materials. The “flux effect” on the WBG semiconductors will be investigated in our forthcoming study, and will be compared with present work.

2. Experimental

2.1. Material and Sample Preparation

The GaAs samples investigated in this study were cut into dimensions of ~10 × 10 mm, from a monocrystalline wafer obtained from a local manufacturer—The Gallium Arsenide Company Slovakia, CMK Ltd. (Zarnovica, Slovakia). Detailed information on the material, provided by the manufacturer, is shown in Table 1.
For the irradiation experiment and subsequent PAS characterisation, in a total, six pairs of samples were required, while one sample pair served as a reference. Two samples were destroyed during the cutting of the sample (Figure 1), and some samples were damaged and thus could not be used for the study evaluated during the proton irradiation.

2.2. Proton Irradiation Experiment

The proton irradiation experiment was performed using the 6 MV Tandetron tandem accelerator at the STU University Science Park CAMBO located in Trnava (Figure 2). The accelerator is used for a wide range of ion irradiation studies including H, He, and heavy ion irradiation. The maximum achievable energy for proton irradiation is 12 MeV and the maximum flux, depending on beam scanning area, which can reach up to 1014 cm−2.s−1 [16].
The actual irradiation times and corresponding proton fluxes shown in Table 2 were proposed according to the availability of the accelerator, in order to obtain a wide range of proton fluxes that will be increasing logarithmically. While different target fluences were initially considered for this experiment, finally a fluence of 1016 cm−2 was selected to be achieved by using five different fluxes (ranging from 1011 to 1113 cm−2.s−1). The energy of the protons in Figure 3 is discussed later in this chapter. The reasoning behind the selection of the fluence is based on the sensitivity of the PALS technique and it is illustrated in Figure 4.
The irradiation temperature was kept near room temperature using a water-cooled sample stage. Figure 3 shows the simulated implantation profile and the values of displacement per atom (dpa) calculated according to the Norgett−Robinson−Torrens (NRT) [18] model using the “The Stopping and Range of Ions in Matter” (SRIM) data obtained according to the suggestion by Stoller [19] for the fluence of 1016 cm−2 used in the present study.
The fundamental approach in this study assumed that the concentration of the radiation-induced point defects would be constant at a certain range of proton flux, but there is a sharp threshold at a certain level of proton flux above which the production of these defects will be diminished in the thermal effects produced by the dislocation cascades.
The SRIM code was used to compute the reference value of the produced concentration of radiation-induced vacancies. However, it is a common understanding that this tool does not consider the mobility of the displaced atoms and the results are obtained for 0 K temperature. Practically, there is always a temperature effect that reduces the number of actual concentrations of vacancies that survived the displacement cascades. Positron annihilation spectroscopy can effectively study this realistic assessment of the concentration of radiation-induced vacancies.
The energy of the charged particles plays a leading role in the type of defects, such as Frenkel pairs, as well as cascade and sub-cascaded collisions. In the presented experiments, energy of 5 MeV was used for the proton irradiation and the resulting sample modification. The corresponding SRIM profile is shown in Figure 3, together with the positron stopping profile obtained from the GEANT4 (GEometry ANd Tracking) simulation package [20]. The figure illustrates the sensitivity of this technique to the given (uneven) defect depth profile by providing the actual/corrected dpa profile, “visible” to 22Na positrons. Energy of 5 MeV was chosen so as to minimise the interaction of positrons with the displacement damage peak and the hydrogen peak produced at the end of the track region by protons capturing electrons.
As mentioned above, the reasoning for selecting the 1016 cm−2 fluence is derived from Figure 4. This fluence can be obtained using realistic flux values and accelerator beam time availability.

2.3. Positron Annihilation Spectroscopy Characterisation

Among the numerous analytical techniques used in material irradiation studies, positron annihilation spectroscopy (PAS) is well known for its spectacular sensitivity to atomic-scale vacancy-type defects. Although the technique is sensitive to other types of defects (dislocations, grain boundaries and precipitates of certain elements), vacancy-type defects are typically the most attractive potential well in irradiated single crystals. The sensitivity of various PAS techniques to neutral vacancies ranges from ~5 × 1015 cm−3 (detection limit) to ~1019 cm−3 (positron trapping gets saturated). This sensitivity range was also considered in the selection of the target fluence in the present experiment.
The experimental characterisation of the irradiated samples was performed at the Slovak University of Technology in Bratislava at the Faculty of Electrical Engineering and Information Technology at the Institute of Nuclear and Physical Engineering. This institute has a dedicated PAS laboratory for positron annihilation spectroscopy equipped with one standalone positron lifetime spectrometer and one setup combining positron lifetime and coincidence Doppler broadening spectrometer. Both lifetime spectrometers are digital, based on three BaF2 scintillator detectors and DRS4 waveform digitising boards.
As mentioned above, the experiment was designed for optimal utilisation of a conventional 22Na positron source with a continuous energy spectrum of positrons ranging from 0 to 540 keV. The actual positron stopping profile, as well as the displacement damage profile adjusted to the spectrum of positron probes, is shown in Figure 3.
For the present research, we used positron annihilation lifetime spectroscopy (PALS), which enables qualitative and quantitative characterisation of vacancy-type defects in crystalline materials. The physical principle of the PALS technique is based on positron trapping by defects and the fact that the positron lifetime depends on the nature and size of this defect. PALS is a widely used microstructural characterisation technique based on the measurement of changes in the time of positrons trapped by lattice defects. Both the size and concentration of defects can be obtained from the positron lifetime spectrumby evaluating the lifetime values and intensities of individual components. The values of the positron lifetimes are well-known for most semiconductors, and the evaluation of the results can be supported by a broad range of published data that are both theoretically and experimentally obtained.

3. Results and Discussion

The positron annihilation lifetime spectra were evaluated using the LT10 program developed by Giebel and Kansy [21]. The spectra were decomposed into two components. The first component characterises the material bulk lifetime t1 (reduced by trapping at defects) and the second component corresponds to lattice defects t2, here considered as monovacancies. The lifetime of the second component was fixed at a value of 295 ps, reported for a mono-vacancies in undoped GaAs [22], while the lifetime of the first component, together with both intensities (I1, I2), was left as a free parameter. The average positron lifetime (tAVG), as the statistically most reliable parameter independent of the fitting model, was calculated for all of the lifetime data. The concentration of vacancies was calculated according to the procedure described in detail, for instance, in [23]. The obtained results are shown in Table 3. The concentration of vacancies NV was directly calculated from the positron trapping rate kv via a constant of proportionality, the so-called trapping coefficient of 1 × 1015 s−1 [22].
The results plotted in Figure 5 show that the proton flux ranges between 1011 and 1012 cm−2.s−1 lead to about the same concentration of monovacancies in 5 ± 1 × 1016 cm−3. This value is fairly reasonable compared with the SRIM simulation, which estimates the vacancy concentration for the given fluence on the level 2.56 × 1017 cm−3. The discrepancy is given by the fact that SRIM does not account for the thermal recombination of vacancies, so SRIM always overestimates the actual damage to the lattice. Considering the aim of this paper, it is interesting to compare the observed vacancy production with other types of irradiation experiments involving PALS analysis. The paper by Sagatova et al. [24] on 8 MeV electron irradiated GaAs reported vacancy concentrations of 1.6 and 2.8 × 1016 cm−3 for samples exposed to 1000 and 1500 kGy radiation. As the latter dose was obtained by 8.37 × 1015 cm−2 electron fluence, i.e., close to the proton fluence 1 × 1016 cm−2 reported in this paper, one can compare the impact of two different types of radiation. Such a comparison suggests that these two types of radiation introduce a similar resulting displacement damage, with only a slightly higher (~factor of 2) concentration of vacancies produced by protons. It is important to note that the analysis was aimed at the ion track region and not the damage peak in both cases.
As can be further seen from Figure 5, at a certain level of proton flux (> 1012 s−1 cm−3) the concentration of radiation-induced vacancies dropped sharply, suggesting that the new displacement damage cascades were initiated while the previous cascades were still active.
On the other hand, it is reasonable to assume that proton fluxes lower than ~1011 s−1 cm−3 would lead to a defect concentration near the saturation range indicated in the figure. From this, we can conclude that proton flux below ~1012 s−1 cm−3 provides a meaningful radiation condition for the accelerated ageing studies in semiconductors planned for application in harsh radiation environments.
This is an important observation for numerous future experiments as it suggests that long exposure to a mild radiation environment can be, to some extent, simulated experimentally by short-term exposure to much more severe radiation conditions. Such a significant shortening of the irradiation experiment can significantly save costs related to beamtime at irradiation facilities.
It is important to note that the observed flux effect could be very different from the flux effect reported for neutron irradiation experiments on reactor pressure vessel (RPV) steels and other types of complex materials, where a higher flux leads to a more significant vacancy-type defect production [25]. Unlike the present experiment, the microstructure of irradiated RPV steels suffers from additional segregation and precipitation of certain elements (such as Cu or P), which the radiation-induced vacancies may be associated with. While the microstructural evolution of semiconductors is relatively simple compared with the nuclear structural materials, the number of published reports on the flux effect in these materials is significantly smaller.
In this study, the electrical properties of the semiconductors were not investigated, but it is reasonable to assume that the concentration of the free charge carriers would result in similar conclusions. However, this will be investigated in more detail in our forthcoming study, additionally including wide-bandgap semiconductors.

4. Conclusions

The present study reports an experimental quantitative characterisation of radiation-induced vacancies in GaAs obtained in proton irradiation experiments using a wide range of proton fluxes. The experimental data were obtained by positron annihilation lifetime spectroscopy, considering the actual stopping profiles of both projectile (proton) and probe (positron) particles. The present research can be summarised as follows:
  • Positron annihilation spectroscopy can be effectively used as a tool for the quantitative characterisation of vacancy-type defects in semiconductors exposed to harsh radiation environments. While the present experiments led to a vacancy concentration near the saturation limit of PAS, the optimal proton fluence for future irradiation experiments can be selected from the range of 1015–1016 cm−2.
  • The results indicate that mild radiation environments involving high-energy protons can be effectively simulated and accelerated by employing relatively high proton fluxes. Moreover, the proton irradiation seems to induce a concentration of vacancy-type defects (mono-vacancies) that is reasonably similar to high-energy electron irradiation experiments with a similar fluence.
  • While SRIM code simulations provide data about the production rates of radiation-induced defects, the presented PAS characterisation enables reliable quantification of the survival rate of the defects. Similar to numerous studies in the past and referenced in this work, the presented experiment can be expanded to include the study of the recovery of the microstructure after thermal annealing of the samples.
  • There is a threshold flux above which the proton irradiation experiment becomes unreasonable and inefficient. This threshold is relatively high and lies above 1012 s−1 cm−2. At a higher proton flux, the new displacement damage cascades are initiated while the previous cascades are still occurring. This results in a sharp reduction in the concertation of the surviving vacancies.
In the next experiment, these conclusions will be used for proposing irradiation studies on other types of semiconductors, including wide bandgap semiconductors. A planned combination of PAS experiments and measurements of the electrical properties of the irradiated materials, such as resistivity and free charge carriers’ concentration, will potentially increase the knowledge about the radiation tolerance of WBG materials, which are inevitable in numerous applications, including space exploration and safety for nuclear power installations.

Author Contributions

Conceptualization, I.N. and V.K.; methodology, I.N., V.K. and P.N.; irradiation experiment P.N.; software, M.P.; investigation, M.P. and S.S.; data curation, I.N. and V.K.; writing—original draft preparation, I.N. and V.K.; writing—review and editing, V.S., P.N. and J.D.; supervision, V.K.; project administration, V.K, J.D., P.N. and V.S.; funding acquisition, P.N. and V.S. All authors have read and agreed to the published version of the manuscript.


The authors would like to acknowledge partial support from the Slovak Research and Development Agency grants No. APVV-20-0010, APVV-20-0220 as well as from the European Regional Development Fund, projects No. ITMS2014+: 313011BUH7 and ITMS2014+: 313011W085. The authors further acknowledge financial contributions from the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic and the Slovak Academy of Sciences, grant number VEGA 1/0395/20.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

All data used to reach the conclusions are presented in the paper. Raw data and experimental logs are available upon request.

Conflicts of Interest

The authors declare no conflict of interest.


  1. Van Tuyl, R.L. The Early Days of GaAs Ics. In Proceedings of the 2010 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS), Monterey, CA, USA, 3–6 October 2010; pp. 1–4. [Google Scholar] [CrossRef]
  2. Pearton, S.J.; Aitkaliyeva, A.; Xian, M.; Ren, F.; Khachatrian, A.; Ildefonso, A.; Kim, J. Review—Radiation Damage in Wide and Ultra-Wide Bandgap Semiconductors. ECS J. Solid State Sci. Technol. 2021, 10, 055008. [Google Scholar] [CrossRef]
  3. Reed, K.; Goetz, C.; Ericson, N.; Sweeney, D.; Ezell, N.D. Wide Bandgap Semiconductors for Extreme Temperature and Radiation Environments; Oak Ridge National Lab: Oak Ridge, TN, USA, 2022. [Google Scholar] [CrossRef]
  4. Kizilyalli, I.C.; Xu, Y.A.; Carlson, E.; Manser, J.; Cunningham, D.W. Current and Future Directions in Power Electronic Devices and Circuits Based on Wide Band-Gap Semiconductors. In Proceedings of the 2017 IEEE 5th Workshop on Wide Bandgap Power Devices and Applications (WiPDA), Albuquerque, NM, USA, 30 October–1 November 2017; p. 417. [Google Scholar] [CrossRef]
  5. Huang, A.Q. Wide bandgap (WBG) Power Devices and their Impacts on Power Delivery Systems. In Proceedings of the 2016 IEEE International Electron Devices Meeting (IEDM), San Francisco, CA, USA, 3–7 December 2016; pp. 20.1.1–20.1.4. [Google Scholar] [CrossRef]
  6. Shenai, K. Future Prospects of Widebandgap (WBG) Semiconductor Power Switching Devices. IEEE Trans. Electron. Devices 2015, 62, 248–257. [Google Scholar] [CrossRef]
  7. Wide-Bandgap Semiconductors for Space Applications; Last Update: 15 February 2022. Record Number: 96633; European Union. 2022. Available online: (accessed on 1 December 2022).
  8. Millán, J.; Godignon, P.; Perpiñà, X.; Pérez-Tomás, A.; Rebollo, J.A. Survey of Wide Bandgap Power Semiconductor Devices. IEEE Trans. Power Electron. 2014, 29, 2155–2163. [Google Scholar] [CrossRef]
  9. Maurer, R.H.; Fraeman, M.E.; Martin, M.N.; Roth, D.R. Harsh Environments: Space Radiation Environment, Effects, and Mitigation. John Hopkins APL Tech. Dig. 2008, 28, 17. [Google Scholar]
  10. Bourban, G. Radiation Environment and its Effects in EEE Components and Hardness Assurance for Space Applications. In Proceedings of the CERN-ESA-SSC workshop European Space Agency ESA, Zurich, Switzerland, 9–10 May 2017. [Google Scholar]
  11. Krstic, M. A Methodology for Characterization, Modeling and Mitigation of Single Event Transient Effects in CMOS Standard Combinational Cells. Doctoral Thesis, Postdam University, Postdam, Germany, April 2022. [Google Scholar] [CrossRef]
  12. Rafí, J.M.; Pellegrini, G.; Godignon, P.; Ugobono, S.O.; Rius, G.; Tsunoda, I.; Moll, M. Electron, Neutron, and Proton Irradiation Effects on SiC Radiation Detectors. IEEE Trans. Nucl. Sci. 2020, 67, 2481–2489. [Google Scholar] [CrossRef]
  13. Summers, G.P.; Burke, E.A.; Shapiro, S.R.; Walters, R.J. Damage correlations in semiconductors exposed to gamma, electron and proton radiations. IEEE Trans. Nucl. Sci. 1993, 40, 1372–1379. [Google Scholar] [CrossRef]
  14. Marshall, P.W.; Dale, C.J.; Summers, G.P.; Wolicki, E.A.; Burke, E.A. Proton, neutron, and electron-induced displacement damage in germanium. IEEE Trans. Nucl. Sci. 1989, 36, 1882–1888. Available online: (accessed on 13 December 2022). [CrossRef]
  15. Väyrynen, S. Irradiation of Silicon Particle Detectors with Mev-Protons; University of Helsinki Report Series in Physics: Helsinky, Finland, 2010; ISBN 978-952-10-5975-9. [Google Scholar]
  16. Advanced Technologies Research Institute. B8405—Specifications and Machine Logs for 6 MV Tandetron System; Internal document of the ATRI MTF STU; Advanced Technologies Research Institute: Tokyo, Japan, 2022. [Google Scholar]
  17. Noga, P.; Száraz, Z.; Kubiš, M.; Dobrovodský, J.; Ferenčík, F.; Riedlmajer, R.; Krsjak, V. High-Fluence Multi-Energy Ion Irradiation for Testing of Materials. Materials 2022, 15, 6443. [Google Scholar] [CrossRef] [PubMed]
  18. Norgett, M.J.; Robinson, M.T.; Torrens, I.M. A proposed method of calculating displacement dose rates. Nucl. Eng. Des. 1975, 33, 50. [Google Scholar] [CrossRef]
  19. Stoller, R.E. On the use of SRIM for computing radiation damage exposure. Nucl. Instrum. Methods Phys. Res. Sect. B: Beam Interact. Mater. At. Vol. 2013, 310, 75–80. [Google Scholar] [CrossRef]
  20. Allison, J.; Amako, K.; Apostolakis, J. Geant4 developments and applications. IEEE Trans. Nucl. Sci. 2006, 53, 270–278. [Google Scholar] [CrossRef][Green Version]
  21. Giebel, G.; Kansy, J. LT10 Program for Solving Basic Problems Connected with Defect Detection. Phys. Procedia. 2012, 35, 122–127. [Google Scholar] [CrossRef][Green Version]
  22. Rehberg, R.K.; Leipner, H.S. Positron Annihilation in Semiconductors; Springer Verlag: Berlin/Heidelberg, Germany, 1999; p. 378. [Google Scholar] [CrossRef]
  23. Krsjak, V.; Degmova, J.; Noga, P.; Petriska, M.; Sojak, S.; Saro, M.; Slugen, V. Application of Positron Annihilation Spectroscopy in Accelerator-Based Irradiation Experiments. Materials 2021, 14, 6238. [Google Scholar] [CrossRef] [PubMed]
  24. Sagatova, A.; Krsjak, V.; Sojak, S.; Riabukhin, O.; Kovacova, E.; Zatko, B. Semi-insulating GaAs detectors degraded by 8 MeV electrons up to 1500 kGy. J. Instrum. 2021, 16, C12032. [Google Scholar] [CrossRef]
  25. Ulbricht, A.; Hernández-Mayoral, M.; Oñorbe, E.; Etienne, A.; Radiguet, B.; Hirschmann, E.; Bergner, F. Effect of Neutron Flux on an Irradiation-Induced Microstructure and Hardening of Reactor Pressure Vessel Steels. Metals 2022, 12, 369. [Google Scholar] [CrossRef]
Figure 1. As-prepared test samples of the GaAs as per Table 1 for the irradiation experiment.
Figure 1. As-prepared test samples of the GaAs as per Table 1 for the irradiation experiment.
Materials 16 01089 g001
Figure 2. The 6 MV Tandetron ion accelerator at the Advanced Technologies Research Institute, Slovak University of Technology [17].
Figure 2. The 6 MV Tandetron ion accelerator at the Advanced Technologies Research Institute, Slovak University of Technology [17].
Materials 16 01089 g002
Figure 3. SRIM-based calculation for the dpa with 5 MeV protons.
Figure 3. SRIM-based calculation for the dpa with 5 MeV protons.
Materials 16 01089 g003
Figure 4. Fluence vs. irradiation times for different proton fluxes (beam currents) used in the experiment.
Figure 4. Fluence vs. irradiation times for different proton fluxes (beam currents) used in the experiment.
Materials 16 01089 g004
Figure 5. The concentration of radiation-induced vacancies in the studied GaAs samples as obtained from the PALS experiments. The concentration predicted by SRIM for 0 K is also indicated.
Figure 5. The concentration of radiation-induced vacancies in the studied GaAs samples as obtained from the PALS experiments. The concentration predicted by SRIM for 0 K is also indicated.
Materials 16 01089 g005
Table 1. Specification of the studied GaAs samples.
Table 1. Specification of the studied GaAs samples.
Product No.82045
MethodGaAs LEC
DescriptionMonocrystalline wafers
TypeSemi-insulating, undoped
Resistivity4.38 × 108 Ohm cm
Hall Mobility5398 Cm2 V−1 s
Orientation(100) ± 0.5°
Off OrientationOff 2° towards (110)°
Diameter50.8 ± 0.1 mm
Thickness500 ± 25 μm
Front sidePolished
Back sideLapped/etched
Table 2. As-prepared test samples for the irradiation experiment.
Table 2. As-prepared test samples for the irradiation experiment.
Sample Set No.Irradiation Time [min]/[h]Flux [cm−2.s−1]
Set 0 (reference)0/00
Set 116/0.271.04 × 1013
Set 236/0.594.63 × 1012
Set 3222/3.707.51 × 1011
Set 4505/8.423.30 × 1011
Set 51599/26.651.04 × 1011
Note, that in two cases (sets 2 and 4), the samples measured using the PAS technique were not identical in terms of the proton fluence received. The proton flux for these samples was calculated as the mean of the two nearest values.
Table 3. Experimental results of the PAS.
Table 3. Experimental results of the PAS.
GaAs Samplesp+ Flux [cm−2]t1 [ps]I1 [%]t2 [ps]I2 [%]tAVG [ps]FVkV [s−1]NV [cm−3]
Set 11.04 × 101322398.98%2951.02%223.70.979.27 × 1064.64 × 1014
Set 24.63 × 101222185.00%29515.00%231.80.931.58 × 1087.92 × 1015
Set 37.51 × 101121550.00%29550.00% × 1084.49 × 1016
Set 43.30 × 101121050.00%29550.00%251.50.998.97 × 1084.49 × 1016
Set 51.04 × 101120346.00%29554.00% × 1095.27 × 1016
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Neuhold, I.; Noga, P.; Sojak, S.; Petriska, M.; Degmova, J.; Slugen, V.; Krsjak, V. Application of Proton Irradiation in the Study of Accelerated Radiation Ageing in a GaAs Semiconductor. Materials 2023, 16, 1089.

AMA Style

Neuhold I, Noga P, Sojak S, Petriska M, Degmova J, Slugen V, Krsjak V. Application of Proton Irradiation in the Study of Accelerated Radiation Ageing in a GaAs Semiconductor. Materials. 2023; 16(3):1089.

Chicago/Turabian Style

Neuhold, Igor, Pavol Noga, Stanislav Sojak, Martin Petriska, Jarmila Degmova, Vladimir Slugen, and Vladimir Krsjak. 2023. "Application of Proton Irradiation in the Study of Accelerated Radiation Ageing in a GaAs Semiconductor" Materials 16, no. 3: 1089.

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop