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The Fifteenth International Conference on

COMPOSITES/NANO ENGINEERING (ICCE 15) Haikou, Hainan Island, China, Hawaii of the Orient, 15-21 July 2007

Committee of ICCE/15 ICCE CONFERENCE CHAIRMAN Professor David Hui Department of Mechanical Engineering University of New Orleans New Orleans, LA 70148 Tel: (504)-280-6652, FAX/Tel:(504)-280-6192, E-mail: [email protected]

ICCE-15 CO-CHAIRS Tamio Endo, Luciano Feo, David Hui, Alan K.T. Lau, Le Quoc Minh, Kunio Wakasa

ICCE-15 Scientific Committee and Review Board

Rodolfo Aoki (German Aero. Res. Cen., Stuttgart, Germany) Alberto Alvarez Castilio (Inst.Tech. Zacatepec, Mexico) Ali Argon (MIT, Mass.) Ramon Artiaga (U. Corona, Spain) L. Ascione (U. Salerno, Italy) Alan Barnes (U. Sheffield, UK) Enrique Barbero (Carlos III Univ. Madrid, Spain) Prof. Enrique Barbero (Universidad Carlos III de Madrid, Spain) Peter Beardmore (Ford Motor Co., MI) Axel Becker (Continental AG, Hanover, Germany) Paul Becker (Oak Ridge N.L., TN) Chris Berndt (SUNY Buffalo, NY) Enric Bertran (U. Barcelona, Spain) Debes Bhattacharyya (U. Auckland, New Zealand) Gonzalo Martinez Barrera (Autonomous University of State of Mexico) V.V. Bolotin (Moscow Power Engineering Inst., Russia) Mircea Chipara (Indiana U.) Wesley Cantwell (U. Liverpool, UK)

K. Matsuura (Hokkaido U., Japan) Frank Matthews (Imperial Coll., UK) L.Neil McCartney (National Physical Lab., Middlesex, UK) Maksim Kireitseu (Institute of Mechanics and Machine Reliability, National Academy of Sciences of Belarus) Ru-shi Liu (Nat. Taiwan U., Taipei) Sergei Mileiko (Solid State Physics Inst., Moscow, Russia) Olivera Milosevic (Inst.Tech. Sci., Belgrade, Yugoslavia) Jiri Militky (TU Liberec, Czech Rep.) Y. Miyamoto (Osaka U., Japan) Herbert Mucha (T.U. Chemnitz, Germany) Francesca Nanni (U. Roma, Italy) Jag Narayan (N. Carolina St.U.) Sia Nemat-Nasser (UC San Diego, Calif.) Anil N. Netravali (Cornell U., NY) Mamoru Noda (Osaka U., Japan) Fumio Nogata (Gifu U., Japan) Andrew Nurse (U. Loughborough, UK)

OXIDE COMPOSITES Oxide Symposium on Oxide Composites, developed by Tamio Endo Surface Analysis of Shocked Bi-Pb-Sr-Ca-Cu-O (BPSCCO) Particles by CCD Hiroshi KEZUKA (Tokyo U.T., Japan) Mon-Thurs Preparation, Structure and Luminescent Spectra of ZnO Nanomaterials LE Quoc Minh, Dinh Xuan Loc, Nguyen Vu (VAST, Hanoi, Vietnam) , David Hui (U. New Orleans), Do Hung Manh, Nguyen Thi Thanh Ngan (VAST, Hanoi), Tamio Endo (Mie U., Japan), TRAN Kim Anh (VAST, Hanoi) 957 Composite of Single-Wall Carbon Nanotube and Tin Oxide for Field Emission Devices Myungchan AN, Hyejin Song, Youngjin Kang, Nguyen Duc Hoa, Nguyen Van Quy, Yousuk Cho, Dojin Kim (Chungnam N.U., Daejeon, Korea) 25 Tin Oxide Coated Single-Walled Carbon Nanotubes For Gas Sensor Application NGUYEN Duc Hoa, Nguyen Van Quy, Myungchan An, Hyejin Song, Youngjin Kang, Yousuk Cho, Dojin Kim (Chungnam Nat. U., Daejeon, Korea) 675 Visible-Light Induced Photocatalytic Activity of N,S Co-Doped TiO2 Yuji OGINO, Toshio Sakai, Hirobumi Shibata, Kenichi Sakai, Takahiro Ohkubo, Hideki Sakai, Masahiko Abe (Tokyo U. Sci., Japan) 705 Lattice Engineering of Perovskite-Type Oxide Thin Films and Nanostructures Yu WANG, X. Y. Zhou, H.L.W.Chan (Hong Kong Poly U., China) 1056 Preparation of Oxidation Protective SiC Coatings for C/SiC Composites by Pulse Chemical Vapor Deposition Haiming WEN, Shaoming Dong, Qing Zhou, Yusheng Ding, Xiangyu Zhang, Ping He (Shanghai Inst.Ceramics, China) 1070 Oxidation Behavior of Polymer Derived SiC Ceramics Yiguang WANG, Houbu Li, Litong Zhang, Laifei Cheng (Northwestern Poly U., Xi’an, China) 1042 Low Temperature Growth Mechanism and Photoluminescence SnO2 Nanowires Bing WANG (Zhongshan U., Guangzhou, China), Tamio Endo (Mie U., Japan), Y.H. Yang, G.W. Yang (Zhongshan U.) Thurs-Friday 1019 Protection of Fe Plate by Organic-Inorganic Materials Via Sol-Gel Process Huey-Chuen KAO (Tamkang U., Tamsui) 432 Superfine Zinc Oxide for Improved Processability and Mechanical Properties of Thermoplastics K.V. Aswathy, Rani JOSEPH (Cochin U. Sci Tech., India) Radiation Stability of Nano Oxide Particles in a 9cr ODS Alloy Jian GAN (Idaho N.L., ID), T. Allen (U. Wisconsin), M. K. Miller (Oak Ridge NL, TN), S. Ukai (Hokkaido U., Japan), S. Shutthanandan, S. Thevuthasan (Pacific Northwewest N.L.) 247 Preparation of Silver-Doped Tin Oxide and its Application to CO Sensing Kan-Sen CHOU, Meng-Syuan Li (Nat.Tsing Hua U., Hsinchu) 175 Synthesis and Characterization of Zno Nanorod by Solid State Reaction Method Rita JOHN, R. Rajakumari (Mother Teresa Women’s U., India) 408 Ion Beam Assisted Deposited Ito Thin Films on Acrylics (PMMA) Substrates Li-Jian MENG (U. Minho, Porto, Portugal), Erjun Liang (Zhengzhou U., China), Jinsong Gao (Changchun, China), V. Teixeira (U. Minho) 631 Optical Properties of Silica Opal Templates in the Infrared and Visible Suppression of Crystal Imperfection Induced Phase Coexistence in Nanometer Sized Single Crystals of La 0.9 Ca 0.1 MnO3 Mark AUSLENDER (Ben Gurion U., Isreal) Preparation of Ceramic Composite Powder Via Layer-by-Layer Method Hiroyuki MUTO, Kazuyuki Shimada, Yusuke Daiko (Toyohashi U.T., Japan),

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PREPARATION, STRUCTURE AND LUMINESCENT SPECTRA OF ZnO NANOMATERIALS Le Quoc Minha*, Dinh Xuan Loca, Nguyen Vua , David Huib Do Hung Manha, Nguyen Thi Thanh Ngana , Tamio Endoc and Tran Kim Anha a

Institute of Materials Science, Vietnamese Academy of Science and Technology 18 Hoang Quoc Viet Road, Cau Giay, Hanoi, Vietnam (Email: [email protected]) b Department Mechanical Engineering, New Orlean University, LA70148 c Graduate School of Engineering, Mie University, Tsu, Mie 514-8507, Japan

Abstract ZnO nanorods were prepared by Chemical Vapor Deposition (CVD), Hydrothermal and Metal Organic Chemical Vapor Deposition (MOCVD) method, respectively. The structure of ZnO nanomaterials were studied by FE-SEM. Aligned growth of ZnO nanorods has been successfully prepared by MOCVD. The nanorods have the diameters of about 30-90 nm, length of about some micrometers. The influence of the temperature and distance from Zn nanopowder sources to substance in the CVD method is investigated. The luminescent spectra (excited by Cd-He laser at 325 nm) of ZnO nanorods at 10K, 12K, 15K, 25K, 35K, 51K and 300 K were measured and investigated. The optimal condition for strong luminescent intensity were investigated and compared. Keywords: ZnO nanorods, MOCVD, CVD, Hydrothermal.

Introduction

Experiment

ZnO nanorods are interesting for both studies and applications because they have wide band gap, large exciton binding energy, high optical gain piezoelectric and pyroelectric multiple properties. ZnO nano structure is specialy attractive for sensors, optoelectronics as well as biomedical by bio safe properties. Recent years, major interests are focused on 1-dimensional nanostructures with hollow interior due to their peculiar and fascinating physical and chemical properties. The review of Prof G C Yi on ZnO nanorods: synthesis, characterization and applications is interesting [1]. ZnO nanorods have enhanced luminescence properties of these 1-dimensional nanostructures, and opened novel application such as making new luminescence devices, new generation of displays and monitors, manufacture of functional materials, new kind of biosensors, emission labels in biology etc. In this paper we will present the preparation and luminescent spectra of the ZnO nanomaterials were prepared by three method of Chemical Vapor Deposition (CVD), Hydrothermal (HT) and Metal Organic Chemical Vapor Deposition (MOCVD).

The sample were grown on Si (111) or sapphiare substrastes by MOCVD, Si (111) wafer covered by one thin layer Pt in the CVD method and using teflon contener in hydrothermal method with not very hight temparature. The morphology of the obtained product has been investigated by FESEM (Hitachi at VAST).Luminescent spectra were measured in Spectrapro 2300 i with Kimmon Laser He-Cd 325 nm or CCD with Titan laser 266 nm.

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Results and discussion Morphology and photoluminescent spectra of ZnO nanomaterials and nanorods prepared at different temparatures (500 0C or 800 0C) and different time (10, 30 or 60 minutes) by different methods were studied. Figure 1 presents FESEM image of ZnO nanomaterials prepared by hydrothermal method at 200 0C.

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diameter and the length of nanorods depend on time prepared. In figure 4, diameter of the rods is about 90 nm when time of 1 h.

Fig.1 FESEM image of ZnO nanomaterials prepared by hydrothermal method at 200 0C. Fig 3. FESEM image of ZnO nanomaterials prepared by CVD method at 800 0C, 10 min.

Fig. 2 FE SEM image of ZnO nanorods prepared by CVD 800 0C, 30 min.

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Fig 4 FESEM image ZnO nanorods by MOCVD method 500 C, 1 h. λ EXC =325 nm

382.6 nm

3000

Intensity (a.u)

ZnO nanorods were grown on Si (100), Al2O3 (0001) substrates using metal organic chemical vapor deposition (MOCVD) [2]. The crystal structure and orientation of ZnO nanorod was investigated [2]. Figure 2 presents FE-SEM images of ZnO sample prepared by CVD method (800 0C, 30 min.). Size and length of nanorods depend on temperature and time as well as the method MOCVD or CVD, the distance between Zn nanopower to the substrate, speed of argon flux, Au or Pt deposition on Si wafer. Figure 3 shows FESEM image of ZnO grown by CVD 800 0C, 10 min. Figure 4 is FESEM image of ZnO Nanorod MOCVD, grown on sapphire substrate at 500oC for 1 hour. One can observed the FE-SEM images in different methods and different conditions are quite different. The diameter as well as the length of nanorods is dependent on technology conditions. From figure 3 the formulated progress of nanorods can be observed. The

Room temprature

2000

1000

0

400

450

500

550

600

650

Wavelength (nm)

Fig.5 PL spectrum of ZnO sample 500oC, 1h prepared by MOCVD.

Photoluminescent (PL) spectra were measured at room temparature and low temperature with different excitations of He-Cd laser 325 nm or Titan Laser of 266 nm. The PL spectra were measured in the case of different methods. The

MOCVD method has good nanorods with blue emission. The hydrothermal method could prepare strong green emission ZnO nanomaterials. This emission is related with defect center in ZnO [1]. Luminescent spectrum of ZnO sample 500oC, 1h prepared by MOCVD was presented in Fig.5. One can notice that luminescent spectrum has one peak at 382.6 nm. From room temperature, PL spectra of ZnO nanorods prepared by MOCVD method exhibits sharp and intense near-band-edge and weak deep-level emission peaks, indicating that the MOCVD-grown ZnO nanorods are of high quality. 60000

ZnO nanorods λEXC = 325 nm

Intensity (a.u)

50000 40000

10K 12K 15K 25K 35K 51K

20000 10000 0 380

390

8

ZnO1a ZnO2a ZnO3a λexc. = 266nm

6

T = 300K

4

2

0 350

Laser line

400

450

500

550

600

650

Wavelength [nm]

Fig.7 PL spectra of ZnO nanomaterials prepared by CVD method 800oC with different distance from 315 cm from Zn nanopowder to substrates. The optimal distance is about 7 cm in this case.

4. Conclusions

30000

370

normalized intensity [a.u.]

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400

Wavelength (nm)

Fig 6 PL spectra the sample ZnO nanorods prepared by MOCVD 500oC, 60 minutes at low temparature of 10K, 12K, 15K, 25K, 35K and 51K after 325 nm excited.

The PL spectra were studied by the Spectrapro 2300i monochromater, used Pixies 256 CCD and Kimmon He-Cd Laser (325 nm), at room temperature. One peak was observed at 3.312 eV with a low excitation intensity of 10 W/cm2. This peak is attributed to the exciton transition bound to neutral acceptors or donor. For the sample ZnO nanorods prepared by MOCVD 500oC, 60 minutes, the PL spectra at low temperature 10 K we can observe some peaks of 3.3473 eV, 3.3213 eV, 3.30186 eV, 3.2079 eV and 3.1113 eV. Temperature dependent was observed with different temperature from 10 K, 12 K, 15K, 25K, 35 K to 51 K. The PL spectra of ZnO nanomaterials prepared by CVD method 800 oC, 30 min.was measured by CCD with 266 nm excited of Titan Sapphiare laser and presented in Figure 7.

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ZnO nanorods and ZnO nanomaterials were prepared by three methods of MOCVD, hydrothermal and CVD. We have obtained ZnO nanorods with diameters range from 30 50 – 90 nm via MOCVD. The length is about some micrometer. ZnO nanorods have strong luminescence in blue region. ZnO nanomaterials were also prepared by hydrothermal with strong green emission. ZnO nanorods were prepared by CVD method and study FE-SEM images, luminescent spectra from 10 K to 51 K.Optimal condition for strong luminescent intensity were studied. Acknowledgements. We would like to thank Prof G.C Yi for his help. The financial support from the basic rsearch program CB 19 and Key Laboratory of Electronic Materials and Devices of Institute of Materials Science, VAST. References [1].Gyu –Chul Yi, Chunrui Wang and Won Il Park, Semicond.Sci.Technol 20 (2005) S22-S34 [2].M. Hoai Nam, D. Xuan Loc, N. Thanh Ngan, L. T Cat Tuong, N. Vu, L.Quoc Minh, T. Kim Anh, Proceedings of the 1st IWOFM-3rd IWONN Conference, Halong, 2006, 703-705.