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Surface modification of LiNbO3 and KTa1−xNbxO3 crystals irradiated by intense pulsed ion beam
Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
Contents lists available at ScienceDirect
Nuclear Instruments and Methods in Physics Research B journal homepage: www.elsevier.com/locate/nimb
Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam Xiaojun Cui a,b,d, Jie Shen a,b, Haowen Zhong a,b, Jie Zhang a,b, Xiao Yu a,b, Guoying Liang a,b, Miao Qu c, Sha Yan c, Xiaofu Zhang a,b, Xiaoyun Le a,b,⇑ a
School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, PR China Beijing Key Laboratory of Advanced Nuclear Energy Materials and Physics, Beihang University, Beijing 100191, PR China Institute of Heavy Ion Physics, Peking University, Beijing 100871, PR China d School of Physics and Technology, University of Jinan, Jinan 250022, PR China b c
a r t i c l e
i n f o
Article history: Received 10 December 2016 Received in revised form 17 March 2017 Accepted 21 March 2017 Available online xxxx Keywords: Intense pulsed ion beam (IPIB) Surface modification LiNbO3 KTa1 xNbxO3
a b s t r a c t In this work, we studied the surface modification of LiNbO3 and KTa1 xNbxO3 irradiated by intense pulsed ion beam, which was mainly composed of H+ (70%) and Cn+ (30%) at an acceleration voltage of about 450 kV. The surface morphologies, microstructural evolution and elemental analysis of the sample surfaces after IPIB irradiation have been analyzed by scanning electron microscope, atomic force microscope, X-ray diffraction and energy dispersive spectrometer techniques, respectively. The results show that the surface morphologies have significant difference impacted by the irradiation effect. Regular gully damages range from 200 to 400 nm in depth appeared in LiNbO3 under 2 J/cm2 energy density for 1 pulse, block cracking appeared in KTa1 xNbxO3 at the same condition. Surface of the crystals have melted and were darkened with the increasing number up to 5 pulses. Crystal lattice arrangement is believed to be the dominant reason for the different experimental results irradiated by intense pulsed ion beam. Ó 2017 Elsevier B.V. All rights reserved.
1. Introduction As a means of material surface processing, intense pulsed ion beam (IPIB) [1] has gained great concern over decades for various surface treating applications [2–4]. The process of IPIB irradiation typically with high density deposition in short duration (10– 1000 ns) [5], the bombardment and thermal effects on the target by the highly compressed radiation energy can realize microstructure changes and super-fast heating in the target surface. As a result, surface hardening, mass ablating, crack healing, novel microstructures generating after IPIB irradiation have been widely studied [6–9]. The applications of IPIB were mainly focused on the surface modification of metal or alloy materials. LiNbO3 (LN) crystal [10] and KTa1 xNbxO3 (KTN) crystal [11] have many advantages for their unique crystal structures and are widely used in electro-optic fields [12–14]. LN crystal belongs to trigonal crystal system, while KTN crystal classified as cubic crystal
⇑ Corresponding author at: School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, PR China. E-mail address: [email protected] (X. Le).
system. There are obvious differences in the crystalline structure and structure symmetry of the two kinds of crystals. In this work, we report, to our knowledge for the first time, on surface modification of LN and KTN crystals irradiated by intense pulsed ion beam. The main purpose of the study are firstly, to investigate the surface modification of the crystals irradiated by IPIB; secondly, to clear the performance of ions in interaction process of IPIB and the crystals; thirdly, to provide the basis for choice of the irradiation parameters. 2. Experimental details The LN and KTN crystals with size of 5 5 1.5 mm3 as the targets were optically polished and cleaned before irradiated by IPIB. The irradiation experiment was performed on the BIPPAB-450 accelerator at Beihang University. The beams from the accelerator was mainly composed of 70% H+ and 30% Cn+, and the ion source was provided by magnetic insulated diode (MID) of polyethylene anode. Typically, the peak value of accelerating voltage and energy density are 450 kV and 2 J/cm2, respectively. The pulse duration is around 80 ns. The samples were irradiated in high vacuum under 1 and 5 pulses, respectively. Surface morphology and composition
http://dx.doi.org/10.1016/j.nimb.2017.03.110 0168-583X/Ó 2017 Elsevier B.V. All rights reserved.
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
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X. Cui et al. / Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
analysis of the samples after irradiation were characterized by using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS, the uncertainties is 2%) on Hitachi S-4800. The roughness of the sample surfaces was measured using atomic force microscope (AFM) on Agilent 5100. The crystal phases were analyzed by X-ray diffraction (XRD) on Rigaku D/MAX2500 device before and after irradiation, respectively.
3. Results and discussion The interaction between IPIB and the targets is governed by the energy deposit effect. As shown in Fig. 1, the spatial distribution of energy in LN crystal and KTN crystal along the depth is simulated by the SRIM-2008 [15]. The incident particles were simulated by the individual H+, C+, as well as the composition of H+ (70%) and C+ (30%) with energy of 450 keV. From the simulation result, the energy loss depth of H+ and C+ in LN crystal is 3.35 lm and 0.75 lm, respectively. The energy loss depth of H+ and C+ in KTN crystal is 3.20 lm and 0.75 lm, respectively. KTN crystal is almost the same with LN crystal.
Fig. 1. Simulated with SRIM-2008 for the energy loss versus the depth in (a) LN crystal and (b) KTN crystal.
Fig. 2. XRD spectrum of (a) LN crystal irradiated by 0, 1, 5 pulse(s), the range from 31.5 to 33.5 is locally enlarged, and (b) KTN crystal irradiated by 0, 1 pulse.
Fig. 2 shows XRD analysis of LN crystal, which was performed to identify the crystal phases before and after IPIB irradiation under 2 J/cm2 energy density. Before irradiation LN crystal exhibited a trigonal structure with apparently (1 1 0) and (2 2 0) orientations. These orientations are consistent with the characteristics of the samples. Irradiation effect caused the peak intensity of (1 0 4) orientation slight increase in LN crystal with the increase of the pulse number, which demonstrated a new (1 0 4) orientation was formed during the melt and recrystallization. The (1 0 0), (2 0 0) and (3 0 0) orientations of KTN crystal are shown in Fig. 3 before and after 1 pulse irradiation, the peak intensities of all orientations of KTN crystal were significantly decreased after irradiation, especially the (2 0 0) orientation. The reason is due to irradiation effect reduced crystallinity in the near surface. The surface morphologies of LN and KTN crystals after IPIB irradiation are investigated by combining SEM with AFM. The SEM photographs irradiated by IPIB under 2 J/cm2 energy density for 1pulse of LN is presented in Fig. 4(A1, A2), and KTN shown in Fig. 4(B1, B2). The radiation energy absorbed by the targets transfers to the lattice and heat is transported into the crystals, the bombard and thermal effects primarily modified the target surfaces. The main cleavage plane of LN can be considered as the crystal plane of the oxygen octahedral field plane located in the lithium ion and niobium ion [10]. This plane is perpendicular to the two weakest ionic bonds, so the crystal stress in the direction perpendicular to the surface is the weakest. In contrast with LN crystal, KTN crystal has the best symmetry and no cleavage plane. From the surface morphology of SEM, the damage of LN crystal surface was mainly concentrated in the place along the cleavage plane, and the regular gully damages range from 200 to 400 nm in depth measured by AFM are shown in Fig. 5. Comparing to LN crystal, the block (dimension in about 10 lm 10 lm) cracking appeared in KTN crystal surface. Crystal lattice arrangement is believed to be the dominant reason for the different surface morphology results irradiated by IPIB. With the increasing of irradiation number, thermal effect induces melting and recrystallization of the targets. Although the point defects occur, the overall surface topography fluctuation decreases from the AFM analysis Fig. 6. The composition of the surface elements affects the surface properties of the crystals. The elemental analysis of the LN surfaces after IPIB irradiation by EDS is shown in Fig. 7(a) and Table 1, the C element is observed at the bottom of the crater, but does not exist on the surface. The percentage of C element is up to 22.97 in the
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
X. Cui et al. / Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
3
Fig. 3. XRD spectrum of KTN crystal irradiated by 0, 1 pulse.
Fig. 4. SEM photographs of (A1, A2) LN crystal and (B1, B2) KTN crystal irradiated by IPIB under 2 J/cm2 energy density for 1 pulse.
crater. Meanwhile, the proportion of O element drops to 49.99. Differently, C element appears in KTN crystal surface after IPIB irradiation from Fig. 7(b) and Table 2. The percentage of C element increased while K, Nb and Ta elements decreased in target 3. Obviously, IPIB irradiation caused the changes of surface composition of LN and KTN crystals.
4. Conclusions Surface modification of LN and KTN irradiated by IPIB is presented in this work. The crystal phases of LN crystal changed slightly after IPIB irradiation, by contrast, the peak intensities of KTN crystal are significantly decreased due to irradiation effect
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
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X. Cui et al. / Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
Fig. 5. The photograph and roughness of the LN crystal surface was measured using AFM after IPIB irradiation under 2 J/cm2 energy density for 1 pulse.
Fig. 6. AFM photographs irradiated by IPIB under 2 J/cm2 energy density for 5 pulses for (a) LN crystal and (b) KTN crystal.
Fig. 7. EDS photographs of (a) LN crystal and (b) KTN crystal after 1 pulse IPIB irradiation under 2 J/cm2 energy density.
Table 1 EDS elemental analysis of LN crystal surface after 1 pulse IPIB irradiation under 2 J/ cm2 energy density. Element (atom %)
C
O
Nb
Target1 Target2 Target3
22.97 ± 1.72% 0.00 ± 0.00% 0.00 ± 0.00%
49.99 ± 1.51% 70.91 ± 2.04% 77.83 ± 1.67%
27.04 ± 0.35% 29.09 ± 0.34% 22.17 ± 0.26%
reduce crystallinity. The regular gully damages range from 200 to 400 nm in depth occur in LN crystal surface, and the block cracking appears in KTN crystal surface by IPIB under 2 J/cm2 energy density for 1 pulse. Crystal lattice arrangement is believed to be the dominant reason for the results. With the increasing of irradiation number, thermal effect induces melting and recrystallization of
Table 2 EDS elemental analysis of KTN crystal surface after 1 pulse IPIB irradiation under 2 J/cm2 energy density. Element (atom %)
C
O
K
Nb
Ta
Target1 Target2 Target3
0.00 ± 0.00% 0.00 ± 0.00% 11.07 ± 0.89%
43.41 ± 1.42% 61.00 ± 1.67% 62.87 ± 1.45%
17.36 ± 0.52% 13.21 ± 0.35% 9.11 ± 0.26%
11.2 ± 0.25% 7.96 ± 0.26% 4.67 ± 0.20%
28.03 ± 1.10% 17.83 ± 0.78% 12.28 ± 0.62%
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
X. Cui et al. / Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
the crystal surfaces. This work can provide reference for the applications of the crystals in the extreme conditions. Acknowledgments This work is supported by National Natural Science Foundation of China (Grant No. 11175012 and 11405073) and National Magnetic Confinement Fusion Program (Grant No. 2013GB109004). References [1] J.M. Neri, D.A. Hammer, G. Ginet, R.N. Sudan, Appl. Phys. Lett. 37 (1) (1980) 101–103. [2] D.J. Rej, H.A. Davis, J.C. Olson, G.E. Remnev, A.N. Zakoutaev, V.A. Ryzhkov, V.K. Struts, I.F. Isakov, V.A. Shulov, N.A. Nochevnaya, et al., J. Vac. Sci. Technol. A 15 (3) (1997) 1089–1097. [3] G.E. Remnev, I.F. Isakov, M.S. Opekounov, V.M. Matvienko, V.A. Ryzhkov, I.I. Grushin, A.N. Zakoutayev, A.V. Potyomkin, V.A. Tarbokov, A.N. Pushkaryov, et al., Surf. Coat. Technol. 114 (2) (1999) 206–212.
5
[4] X.Y. Le, S. Yan, W.J. Zhao, B.X. Han, Y.G. Wang, J.M. Xue, Surf. Technol. 54 (11) (2003) 745–748. [5] Y. Xiao, J. Shen, M. Qu, W.B. Liu, H.W. Zhang, J. Zhang, Y.Y. Zhang, S. Yan, G.L. Zhang, X.F. Zhang, et al., Vacuum 113 (2015) 36–42. [6] D.C. Mcintyre, E.L. Neau, R.W. Stinnett, Adv. Mater. Processes 5 (1999) 31. [7] D. Wu, Y. Gong, J.Y. Liu, X.G. Wang, Y. Liu, T.C. Ma, Surf. Coat. Technol. 201 (9) (2007) 5090–5092. [8] J. Shen, X. Yu, Y.Y. Zhang, H.W. Zhong, J. Zhang, M. Qu, S. Yan, G.L. Zhang, X.F. Zhang, et al., Nucl. Instrum. Meth. Phys. Res. B 365 (2015) 26–29. [9] Z.H. Dong, Z. Zhang, C. Liu, X.P. Zhu, M.K. Lei, Appl. Surf. Sci. 253 (2006) 2563– 2564. [10] R.S. Weis, T.K. Gaylord, Appl. Phys. A 37 (4) (1985) 191–203. [11] U.T. Höchli, H.E. Weibel, L.A. Boatner, Phys. Rev. Lett. 39 (18) (1977) 1158– 1161. [12] J.A. Giordmaine, R.C. Miller, Phys. Rev. Lett. 14 (24) (1965) 973–976. [13] X.L. Wang, K.M. Wang, F. Chen, G. Fu, S.L. Li, H. Liu, L. Gao, D.Y. Shen, H.J. Ma, R. Nie, Appl. Phys. Lett. 86 (4) (2005) 041103. [14] L.L. Wang, X.L. Wang, F. Chen, K.M. Wang, F. Lu, H.J. Zhang, X.P. Wang, H.J. Ma, Jpn. J. Appl. Phys. 46 (9R) (2007) 5885–5888. [15] J.F. Ziegler, J.P. Biesack, U. Littmark, The Stopping and Ranges of Ions in Matter, Pergamon, New York, 1985.
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
Contents lists available at ScienceDirect
Nuclear Instruments and Methods in Physics Research B journal homepage: www.elsevier.com/locate/nimb
Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam Xiaojun Cui a,b,d, Jie Shen a,b, Haowen Zhong a,b, Jie Zhang a,b, Xiao Yu a,b, Guoying Liang a,b, Miao Qu c, Sha Yan c, Xiaofu Zhang a,b, Xiaoyun Le a,b,⇑ a
School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, PR China Beijing Key Laboratory of Advanced Nuclear Energy Materials and Physics, Beihang University, Beijing 100191, PR China Institute of Heavy Ion Physics, Peking University, Beijing 100871, PR China d School of Physics and Technology, University of Jinan, Jinan 250022, PR China b c
a r t i c l e
i n f o
Article history: Received 10 December 2016 Received in revised form 17 March 2017 Accepted 21 March 2017 Available online xxxx Keywords: Intense pulsed ion beam (IPIB) Surface modification LiNbO3 KTa1 xNbxO3
a b s t r a c t In this work, we studied the surface modification of LiNbO3 and KTa1 xNbxO3 irradiated by intense pulsed ion beam, which was mainly composed of H+ (70%) and Cn+ (30%) at an acceleration voltage of about 450 kV. The surface morphologies, microstructural evolution and elemental analysis of the sample surfaces after IPIB irradiation have been analyzed by scanning electron microscope, atomic force microscope, X-ray diffraction and energy dispersive spectrometer techniques, respectively. The results show that the surface morphologies have significant difference impacted by the irradiation effect. Regular gully damages range from 200 to 400 nm in depth appeared in LiNbO3 under 2 J/cm2 energy density for 1 pulse, block cracking appeared in KTa1 xNbxO3 at the same condition. Surface of the crystals have melted and were darkened with the increasing number up to 5 pulses. Crystal lattice arrangement is believed to be the dominant reason for the different experimental results irradiated by intense pulsed ion beam. Ó 2017 Elsevier B.V. All rights reserved.
1. Introduction As a means of material surface processing, intense pulsed ion beam (IPIB) [1] has gained great concern over decades for various surface treating applications [2–4]. The process of IPIB irradiation typically with high density deposition in short duration (10– 1000 ns) [5], the bombardment and thermal effects on the target by the highly compressed radiation energy can realize microstructure changes and super-fast heating in the target surface. As a result, surface hardening, mass ablating, crack healing, novel microstructures generating after IPIB irradiation have been widely studied [6–9]. The applications of IPIB were mainly focused on the surface modification of metal or alloy materials. LiNbO3 (LN) crystal [10] and KTa1 xNbxO3 (KTN) crystal [11] have many advantages for their unique crystal structures and are widely used in electro-optic fields [12–14]. LN crystal belongs to trigonal crystal system, while KTN crystal classified as cubic crystal
⇑ Corresponding author at: School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, PR China. E-mail address: [email protected] (X. Le).
system. There are obvious differences in the crystalline structure and structure symmetry of the two kinds of crystals. In this work, we report, to our knowledge for the first time, on surface modification of LN and KTN crystals irradiated by intense pulsed ion beam. The main purpose of the study are firstly, to investigate the surface modification of the crystals irradiated by IPIB; secondly, to clear the performance of ions in interaction process of IPIB and the crystals; thirdly, to provide the basis for choice of the irradiation parameters. 2. Experimental details The LN and KTN crystals with size of 5 5 1.5 mm3 as the targets were optically polished and cleaned before irradiated by IPIB. The irradiation experiment was performed on the BIPPAB-450 accelerator at Beihang University. The beams from the accelerator was mainly composed of 70% H+ and 30% Cn+, and the ion source was provided by magnetic insulated diode (MID) of polyethylene anode. Typically, the peak value of accelerating voltage and energy density are 450 kV and 2 J/cm2, respectively. The pulse duration is around 80 ns. The samples were irradiated in high vacuum under 1 and 5 pulses, respectively. Surface morphology and composition
http://dx.doi.org/10.1016/j.nimb.2017.03.110 0168-583X/Ó 2017 Elsevier B.V. All rights reserved.
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
2
X. Cui et al. / Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
analysis of the samples after irradiation were characterized by using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS, the uncertainties is 2%) on Hitachi S-4800. The roughness of the sample surfaces was measured using atomic force microscope (AFM) on Agilent 5100. The crystal phases were analyzed by X-ray diffraction (XRD) on Rigaku D/MAX2500 device before and after irradiation, respectively.
3. Results and discussion The interaction between IPIB and the targets is governed by the energy deposit effect. As shown in Fig. 1, the spatial distribution of energy in LN crystal and KTN crystal along the depth is simulated by the SRIM-2008 [15]. The incident particles were simulated by the individual H+, C+, as well as the composition of H+ (70%) and C+ (30%) with energy of 450 keV. From the simulation result, the energy loss depth of H+ and C+ in LN crystal is 3.35 lm and 0.75 lm, respectively. The energy loss depth of H+ and C+ in KTN crystal is 3.20 lm and 0.75 lm, respectively. KTN crystal is almost the same with LN crystal.
Fig. 1. Simulated with SRIM-2008 for the energy loss versus the depth in (a) LN crystal and (b) KTN crystal.
Fig. 2. XRD spectrum of (a) LN crystal irradiated by 0, 1, 5 pulse(s), the range from 31.5 to 33.5 is locally enlarged, and (b) KTN crystal irradiated by 0, 1 pulse.
Fig. 2 shows XRD analysis of LN crystal, which was performed to identify the crystal phases before and after IPIB irradiation under 2 J/cm2 energy density. Before irradiation LN crystal exhibited a trigonal structure with apparently (1 1 0) and (2 2 0) orientations. These orientations are consistent with the characteristics of the samples. Irradiation effect caused the peak intensity of (1 0 4) orientation slight increase in LN crystal with the increase of the pulse number, which demonstrated a new (1 0 4) orientation was formed during the melt and recrystallization. The (1 0 0), (2 0 0) and (3 0 0) orientations of KTN crystal are shown in Fig. 3 before and after 1 pulse irradiation, the peak intensities of all orientations of KTN crystal were significantly decreased after irradiation, especially the (2 0 0) orientation. The reason is due to irradiation effect reduced crystallinity in the near surface. The surface morphologies of LN and KTN crystals after IPIB irradiation are investigated by combining SEM with AFM. The SEM photographs irradiated by IPIB under 2 J/cm2 energy density for 1pulse of LN is presented in Fig. 4(A1, A2), and KTN shown in Fig. 4(B1, B2). The radiation energy absorbed by the targets transfers to the lattice and heat is transported into the crystals, the bombard and thermal effects primarily modified the target surfaces. The main cleavage plane of LN can be considered as the crystal plane of the oxygen octahedral field plane located in the lithium ion and niobium ion [10]. This plane is perpendicular to the two weakest ionic bonds, so the crystal stress in the direction perpendicular to the surface is the weakest. In contrast with LN crystal, KTN crystal has the best symmetry and no cleavage plane. From the surface morphology of SEM, the damage of LN crystal surface was mainly concentrated in the place along the cleavage plane, and the regular gully damages range from 200 to 400 nm in depth measured by AFM are shown in Fig. 5. Comparing to LN crystal, the block (dimension in about 10 lm 10 lm) cracking appeared in KTN crystal surface. Crystal lattice arrangement is believed to be the dominant reason for the different surface morphology results irradiated by IPIB. With the increasing of irradiation number, thermal effect induces melting and recrystallization of the targets. Although the point defects occur, the overall surface topography fluctuation decreases from the AFM analysis Fig. 6. The composition of the surface elements affects the surface properties of the crystals. The elemental analysis of the LN surfaces after IPIB irradiation by EDS is shown in Fig. 7(a) and Table 1, the C element is observed at the bottom of the crater, but does not exist on the surface. The percentage of C element is up to 22.97 in the
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
X. Cui et al. / Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
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Fig. 3. XRD spectrum of KTN crystal irradiated by 0, 1 pulse.
Fig. 4. SEM photographs of (A1, A2) LN crystal and (B1, B2) KTN crystal irradiated by IPIB under 2 J/cm2 energy density for 1 pulse.
crater. Meanwhile, the proportion of O element drops to 49.99. Differently, C element appears in KTN crystal surface after IPIB irradiation from Fig. 7(b) and Table 2. The percentage of C element increased while K, Nb and Ta elements decreased in target 3. Obviously, IPIB irradiation caused the changes of surface composition of LN and KTN crystals.
4. Conclusions Surface modification of LN and KTN irradiated by IPIB is presented in this work. The crystal phases of LN crystal changed slightly after IPIB irradiation, by contrast, the peak intensities of KTN crystal are significantly decreased due to irradiation effect
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
4
X. Cui et al. / Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
Fig. 5. The photograph and roughness of the LN crystal surface was measured using AFM after IPIB irradiation under 2 J/cm2 energy density for 1 pulse.
Fig. 6. AFM photographs irradiated by IPIB under 2 J/cm2 energy density for 5 pulses for (a) LN crystal and (b) KTN crystal.
Fig. 7. EDS photographs of (a) LN crystal and (b) KTN crystal after 1 pulse IPIB irradiation under 2 J/cm2 energy density.
Table 1 EDS elemental analysis of LN crystal surface after 1 pulse IPIB irradiation under 2 J/ cm2 energy density. Element (atom %)
C
O
Nb
Target1 Target2 Target3
22.97 ± 1.72% 0.00 ± 0.00% 0.00 ± 0.00%
49.99 ± 1.51% 70.91 ± 2.04% 77.83 ± 1.67%
27.04 ± 0.35% 29.09 ± 0.34% 22.17 ± 0.26%
reduce crystallinity. The regular gully damages range from 200 to 400 nm in depth occur in LN crystal surface, and the block cracking appears in KTN crystal surface by IPIB under 2 J/cm2 energy density for 1 pulse. Crystal lattice arrangement is believed to be the dominant reason for the results. With the increasing of irradiation number, thermal effect induces melting and recrystallization of
Table 2 EDS elemental analysis of KTN crystal surface after 1 pulse IPIB irradiation under 2 J/cm2 energy density. Element (atom %)
C
O
K
Nb
Ta
Target1 Target2 Target3
0.00 ± 0.00% 0.00 ± 0.00% 11.07 ± 0.89%
43.41 ± 1.42% 61.00 ± 1.67% 62.87 ± 1.45%
17.36 ± 0.52% 13.21 ± 0.35% 9.11 ± 0.26%
11.2 ± 0.25% 7.96 ± 0.26% 4.67 ± 0.20%
28.03 ± 1.10% 17.83 ± 0.78% 12.28 ± 0.62%
Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110
X. Cui et al. / Nuclear Instruments and Methods in Physics Research B xxx (2017) xxx–xxx
the crystal surfaces. This work can provide reference for the applications of the crystals in the extreme conditions. Acknowledgments This work is supported by National Natural Science Foundation of China (Grant No. 11175012 and 11405073) and National Magnetic Confinement Fusion Program (Grant No. 2013GB109004). References [1] J.M. Neri, D.A. Hammer, G. Ginet, R.N. Sudan, Appl. Phys. Lett. 37 (1) (1980) 101–103. [2] D.J. Rej, H.A. Davis, J.C. Olson, G.E. Remnev, A.N. Zakoutaev, V.A. Ryzhkov, V.K. Struts, I.F. Isakov, V.A. Shulov, N.A. Nochevnaya, et al., J. Vac. Sci. Technol. A 15 (3) (1997) 1089–1097. [3] G.E. Remnev, I.F. Isakov, M.S. Opekounov, V.M. Matvienko, V.A. Ryzhkov, I.I. Grushin, A.N. Zakoutayev, A.V. Potyomkin, V.A. Tarbokov, A.N. Pushkaryov, et al., Surf. Coat. Technol. 114 (2) (1999) 206–212.
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Please cite this article in press as: X. Cui et al., Surface modification of LiNbO3 and KTa1 xNbxO3 crystals irradiated by intense pulsed ion beam, Nucl. Instr. Meth. B (2017), http://dx.doi.org/10.1016/j.nimb.2017.03.110