20(1) fm

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1 Krean J. Crystallgraphy Vl. 20, N. 1, pp.1~8, 2009 Ÿ (ICISS) w š t w (3): t w y w œw Surface Structure Analysis f Slids by Impact Cllisin In Scattering Spectrscpy (3): Surface Structure f Ceramics Yen Hwang Department f Materials Science & Engineering, Seul Natinal University f Technlgy, Seul , Krea Ÿ (ISS: In Scattering Spectrscpy) t s z (RBS: Rutherfrd Backscattering Spectrscpy) œ w. ƒ 180 š w» ew Ÿ (ICISS: Impact Cllisin In Scattering Spectrscpy) w» w š, d t d ¾ w ƒ w. w w x(tof: Time-Of-Flight)» kw d w t y y t w p w š w. š ICISS, e, d w 1r t, / w w» w 2 r t,,», r w wš w. 1. t w t p w w w. p,», t p w w v w. 1) ky» ù, w j y t, t / d, w, r (segregatin) Ÿw w y» w t w w. w w» w ƒ t d y g y d x w z ƒ Ÿ w w w ƒ y d j ƒ š. ù 2-4) (stichimetry), Ì (unifrmity), w (directinality). ICISS w t w w x» kw ƒ d t š. t LiNbO 3, 5) BaTiO 3, 6) MgO, 7) HfC w ƒ 8). 1.1 LiNbO 3 (001) LiNbO 3 c- w (Li Nb) 1

2 황연 2 Fig. 1. (a) Intensity variatin f the measured and the simulated Nb spectra alng the [210] azimuth as a functin f plar angle frm 10 t 90. (b) Ball mdel illustratin f the face cut alng the [210] azimuthal directin. 5) 한국결정학회지 Fig. 2. (a) Intensity variatin f the measured and the simulated Nb spectra alng the [100] azimuth as a functin f plar angle frm 10 t 90. (b) Ball mdel illustratin f the face cut alng the [100] azimuthal directin. 5) 원자의 면이 교대로 적층되는 구조를 갖고있다. 따라서 (001) 면의 최외층에 자리하는 원자에 대 하여 연구 되었다. Fig. 1 은 LiNbO (001) 면에서 [210] 방위로 Nb 원자에 대하여 측정한 ICISS 산 란 강도이다. 이 방향으로 놓인 수직 면에는 산소 원자가 위치하지 않으며, Li 원자의 산란강도는 매우 작아서 무시할 만 하다. Fig. 1 을 보면 실험 과 계산이 잘 일치하고 있다. 한편 [100] 방위로 놓인 수직면에는 최외층에 O 나 Nb 원자가 자리 할 수 있는데, 최외층 원자의 종류에 상관없이 계 산결과는 실험과 맞지 않는다 (Fig. 2). 이러한 불 일치는 최외층의 O 원자의 위치를 수직 또는 수 평 방형으로 변화시키고 계산하여도 해소되지 않 5) 3 는다. 따라서 LiNbO (001) 면의 최외층의 O 원자 에는 점 결함 또는 적층 결함이 다수 존재하는 것 으로 생각된다. 면의 구조 HfC는 IV족 전이금속 탄화물로서 암염형 결정구 조를 가지고 있다. 융점은 3950 C 로서 매우 높고, 비저항은 45 µωcm로 금속 성질을 가진다. 전자구 조는 이온, 공유, 금속 결합을 동시에 나타내는 것 이 특징이고, 응용 분야는 코팅재료, 보강재, 원자 로 벽, 전자방사 재료, 촉매 등이 있다. Fig. 3 은 Li 이온을 사용한 HfC(111) 청정표면의 ICISS 스 HfC(111) +

3 20«1y, 2009 Ÿ (ICISS) w š t w (3): 3 Fig. 3. ICISS spectra f clean HfC(111) surface. The scattering angle is 160. The dts are experimental and the slid lines are calculated results, respectively. 8) rp. w 8) [110], [112], [112] 3ƒ. ùkù shadwing blcking z w ƒ Fig. 4 ƒ e ùkü. Fig. 3(b) 73.9 shadwing 1d Hf l 3d Hf w ƒ w 1d 3d ƒ w. 1d t 0.18Û 0.05 Å y. j 1d 2d 13.4% w. HfC IV y w TiC(111) t 30% y š š. 9) Fig. 3(c) 51.7 shadwing vj 2d C l 3d Hf z w ƒ l 2d 3d w š, j Fig. 4. Schematic diagrams shwing the shadwing and blcking effects f Fig. 3. All diagrams are drawn frm side views. 8) w. 2d k d y MgO/TiC(001) Fig. 5 TiC(001) MgO Ti Mg w ƒ w y ùkü. 10) TiC(001) 2keV He + w [110] w ƒ y j 5 vjƒ ùkú. [100] w ƒ [110] w» 3 vj ùkù. [110] ƒ w j ¾ d. Fig. 6 Fig. 5 ùkú 6 vj ùküš. t 1d l 4d

4 4 y w wz Fig. 5. Plar angle scanning f Ti and Mg peak intensities in TOF-ICISS at the clean and MgOdepsited TiC(001) surface alng the [110] azimuth. The intensity f Mg in MgO/TiC(001) was magnified by 5 times. 10) Fig. 6. Schematic view f the shadw cnes fr 2 kev He+ ins impinging n the TiC(001) surface alng the [110] azimuth. Small and large circles represent carbn and titanium atms, respectively. 10) w C Ti w shadw cne 16, 26, 44, ƒ z ùküš, x e w. l TiC(001) x MgO e Ì w. channeling ùš d ƒ a=90»q Ti ƒ š, ƒ ƒ 80 w Ti vjƒ» w. Mg O»q n-tp site š w. MgOƒ z TiC(001) 4d v jƒ. MgO 3d ü w. MgO/TiC(001) t Ti Mg vj e, ƒ ƒ x ü ewš, Ti vj e z mw w. w ƒ MgOƒ TiC(001) t Ti w. l MgO t sw w TiC. MgO»q w š»q l» ƒ x Ti û». û ƒ [110] [100] w x ù vj vjƒ MgO œœ q. Mg y MgO y 11) y ù Mg O yy w MgO x MgO Mg O ƒ yw š. 2.2 BaTiO 3 /MgO(100) MgO BaTiO 3 4.8%»q k. MgO(100) t BaTiO 3 w» w TiO 2 g w. x ƒ 12) BaO

5 20«1y, 2009 Ÿ (ICISS) w š t w (3): 5 [011] w ƒ MgO(100) [001] w w 45 z w MgO(100) t vk ƒ w, BaO d ö w w» vk. TiO 2 MgO t w w ö w. Fig. 7 TiOƒ MgO(100) w ƒ ¾ y g [001] [011] w w ùk ù TOF-ICISS rp y. 13) MgO(100) t TiO w z vj»q w z w ƒ ùkùš. TiO Fig. 7. Plar angle scan f Mg and Ti peak intensities at the clean and TiO depsited MgO(100) surfaces alng the [001] and [011] azimuth. The incident angle is frm the surface. The intensity f Mg peak was magnified by 5 times t cmpare with that f the Ti peak. 13) Fig. 8. Plar angle scan f Ti and Ba peak intensities in TOF-ICISS alng the [001] azimuth at the BaTiO 3 depsited MgO(100) surface after annealing at 800 C. The intensity f Ti peak was magnified by 5 times t cmpare with that f the Ba peak. 13)»q x š w. 14,15) TiOƒ t BaO w z w Ba, Ti, O ƒ y y w x w. Fig C 10 w z r z ùkü, Ti l ù z ƒ ƒ w yw š Ba l z ƒ ùkùš. w ƒ l w w» w [001] w w w Ti l z w 74, 41, 36, 20 wš Ba z 75, 58, 32, 15 ù. Fig. 8 d Ti 74, 44, 34, 22 Ba 74, 58, 32, 16 x ü ewš. w [011] w w ƒ z ƒ BaTiO 3 l w. Ba, Ti, O yw ƒ ƒ ù BaTiO 3 wš ƒ MgO š w. w»q l t w ICISS ƒ ¾ TiO BaO w ƒ

6 6 y w wz w TiO BaO 1 ƒ¾. w r v e p w w ƒ x ew BaTiO 3. TiO wš r v e p, TiO 2ƒ TiO». MgO TiO ƒ š, w y» 16,17) Ti O y y w MgO t TiO x w. BaO MgO ƒ TiO t vk w š, z mw r v e p BaTiO 3 k. 3.» ICISS š t» e w. HfC(111) t 3L j LEED ql 1Ü 1 w t ù. e w» w w ICISS Fig. 9 ùkü. 8) [110] O w shadwing ùkù. O [110] l Hf ƒ e, 3-fld site ew. [112] [112] rp O l Hf shadwing O eƒ š, Fig. 10 ùkü. w w Fig. 9. ICISS spectra f a O-HfC(111) surface. Open circles are clean surface and filled circles are adsrbed xygen, respectively. The lines are calculated results. 8) Fig. 10. Atmic structure f O-HfC(111) surafce. 8)

7 20«1y, 2009 Ÿ (ICISS) w š t w (3): 7 3d Hf 3-fld site. HfC t 1d l 2.10 Å ƒ w w.»k» ù w l l q w w š š w. 4. r w t r x, œ w. ù w t 18,19) r x (LE) ISS w d ƒ w. ù w w š t r t w w w ISS w. w LEISS m š t l y š y» w» t l ¾ d. w e w ù wì w w wš ) Fig. 11 TiC(001) t Ta 2MeV ƒ» w insácm w z 2keV He w + [110] [100] d w ICISS l. 23) TiC (001) t [110] ùkù z 5. Ta r e w. Ta Ti z w vj ƒ ùkù. Ta ƒ TiC j y j Ti ƒ w. Ta ƒ C ƒ Ti C j ù» Ti z ƒ ƒ ùkù w. Ta d w w ¾ d. Ta Ti vj ƒ ƒ û f. Ta t ¾ û. d Ta 4d w 2. MgO(001) Ca Eu r w. 24,25) š x Fig. 11. Plar angle scattering f Ta and Ti peak intensities in TOF-ICISS spectra at the Tasegregated TiC(001) surface alng the [110] azimuth (a), and [100] azimuth (b). The intensity f Ta was magnified by 3 times. 23) 1) Henrich, V. E. and Cx, P. A., The Surface Science f Metal Oxides (Cambridge University Press, Cambridge, 1994). 2) Thiry, P. A., Ghijsen, J., Sprken, R., Pireaux, J. J., Jhnsn, R. L. and Caudan, R., Phys. Rev., B39, 3620 (1989). 3) Peng, X. D. and Barteau, M. A., Surf. Sci., 233, 283 (1990). 4) Gassmann, P., Franchy, R. and Ibach, H., Surf. Sci., 319, 953 (1994). 5) Tabata, K., Chs, T., Murakami, A. and Suzuki, E., Surf. Sci, , 487 (1998). 6) Yshimt, M., Maeda, T., Shimzn, K., Kinuma, H., Shinhara, M., Ishiyama, O. and

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