Khả năng ứng dụng các dây nano zno được chế tạo bằng phương pháp bốc bay nhiệt

DAI HOC QUOC GIA HA NOI TRUONG OAI HOC KHOA HOC TU NHIEN • • • * * • * V\ bl TA\l! KHA NANG LTNG DUNG CAC DAY NANO ZnO Dl/OC CHE TAO BANG PHl/ONG PHAP BOG BAY NHIET MA SO: I QT - 06 - 09 CHU TRI DE TAI: PCS TS Ta Dinh Canh CAN CN Tran Thi Quynh Hoa BO THAM GIA: CN Nguyen Viet Tuyen HA Ndi - 2006 ^^Al H O C Q O O C GIA HA NQI i^UN tomi tji,/)c itiii lltir IV, Can Tlio l5-l9/ii/2(K)6 I{T) = /(O) \ + Ae where 7(0) is the emission intensity at K, /( is a constant, E is activation energy of the thermal quenching process and kn is Boltzmann constant By curve fating^the experimental data in Fig 10, we found that E= 13.5 meV and 42.3 meV for D^'X and BF peaks, respectively The value of 13.5 meV is close to the value of the binding energy of the exciton bound to the neutral donors, experimentally obtained to be 12 meV [5] The value of 42.3 meV being larger than thermal activation energy at room temperature (- 26 meV) indicates possibility of existence of BF peak at high temperatures FWHM (F) of peak D^'X, BF as a function of temperature is shown in Fig 11 It was found that FWHM could be fitted by following [6]: 0.5 e •• -1 (BF)F-,, -72.5mrV 0.4 where r(0) is the broadening parameter at K, F/^ , V,^^ are parameter measured = 0.3 weighting of LA, LO phonons, 0.2 respectively, and E^Q is the energy of LO o O phonons (i> \^^ Fi\>m the fitting we obtain A'/M - 73.*^ 0(1 ton iflo 200 •i^i\ and 72.5 meV for D"X and BF peak, respectively Such values are in well Fig II: The observed FWHM of D'X agreement with the previously reported and BF peak as a function of temperature value of 72 meV The broad peak at about 3.113 eV (peak IV) is interpreted as a donor - acceptor pairs (DAP) emission The position of DAP emission is described as: lriti|n'iiiliiiv ( k ) h\' = E-(E_,+E,,) + tr where Eg is the band gap, E^ and Ep are the acceptor and donor binding energy, respectively, q is the electrical charge of the acceptor and donor ions, E is the dielectric constant, and r is the donor - acceptor distance With increasing temperature, carriers on donor-acceptor pairs with small distance r are released into the band, which results in extinguishing the high-energy side of DAP emission line, and the line is shifted to the low-energy side as observed in our experiment CONCLUSIONS In summary, the ZnO nanowires have been fabricated by controlling the conditions of the vapor - phase transport The ZnO nanowires with diameter of about 40 - 150 nm and lengths to tens of micrometer show the typical wurtzite crystal structure The growth process is explained by means of a VLS mechanism The PL spectra of ZnO nanowires in the near band edge region were investigated in temperature range from 14.5 K to 300 K Four UV emission peaks were attributed to neutral donor - bound exciton (D"X), recombination of an electron bound on Bdo cdo Hpi nghj Quang hoc Quang phd todn qudc hht fhdIV, Cdn Tho' I5-I9/S/2006 donor with a free hole in the valence band (BF), phonon replica ofthe peak BF with one LO - phonon energy (BF-LO), donor - acceptor pairs (DAP) Acknowledgements This work is supported by Natural Science Council Ministry of Science and Technology of Vietnam (Project N" 811304) Authors of this paper would tike to express their sincere gratitude to the Center for Materials Science (CMS), Faculty of Physics, University ofScience, Hanoi National University for permission to use equipment REFERENCES [1] TK J Gupta, Am Cei-am Soc, 73 (7), (1990), 1817 [2] Y R Varshni, Physica (Amsterdam), 34, (1967), 149 [3] D H Chi, L T T Binh, N T Binh, L D Khanh, N N Long, Appl Surf Scien., 252, (2006), 2770 [4] PO Holtz, B Monemar, H J Lozykowski, Phys Rev ,B 32, (1985), 986 [51 H.J Ko, Y F Chen, Z Zhu, T Yao, ( Kobayashi, II Uchiki, Appl Phys Lett 76 (2000)1905 [6] T Makino, C.H Chia, N N Tuan, Y Segawa, M Kawasaki, A Ohtomo, K Tamura, H Koinuma, App Phys LeU ,76, (2000), 349 DAI HOC QUOC GIA HA NOI TRCCINC DAI HOC KHOA HOC Tl/NHlfiN KHOA VAT L t ca \V TIEN LOG /v^ ^ /v^ CHE TAO MOT SO CAU TRUC NANO ZnO BANG PHUONG PHAP BOC BAY NHIET KHOA LUAN TOT NGHIEP HE DAI HOC CHINH QUY NGANIi VAT LY Giao vien huong dim: PGS.TS Ta Dinh Ganh Giao vien phan bien: PGS.TS Le Van Vu la n o i - 0 MUC LUC • Jl _ • ^^ MO DAU CHirONG TONG QUAN L f THUYfiT 1.1 L^ THUYET \ t SU GIAM GIU LUONG TLT 1.1.1 Sir giam giu lugng tu 1.1.2 Gieng lugmg tu 1.2 T6NG QUAN VE BAN DAN ZnO 1.2.1 Mot so thong so tong qiuit cua ban dSn ZnO 1.2.2 ca'u triic tinh the ciia ZnO 1.2.3 Ca'u true phat trien dien hinh ciia ZnO 1.2.4 Tinh chat va trien vung ap dung ciia ban dSn ZnO a Tinh chat cjujin^ b Tinh :ip ^ c Mot so irng dung 10 CHUONG PHUONG PHA? THUC NGHIEM 12 2.1 Cac phuang phap tung hop cau tnic mot chieu 2.2 Cac phep phan (ich v;i dac 12 14 2.3 Quy trinh tao in^u 17 CHUONG KET QUA VA THAO LUAN 20 3.1 Hinh thai va cau triic 20 3.2 Co che phat trien ciia cac cau triic nano ZnO 24 K^TLUAN 29 TAI LIEU THAM KHAO 30 Ui noi -2006 DAI HOC QUOC GIA HA NOI TRUClNCi DAI HOC KHOA HOC TI/NHI£N Q Nguyen Viet Tuyen DE TAI CHE TAO VA KHAO SAT DIA NANO DANG LOI/VO CUA Zn/ZnO BANG PHUONG PHAP BOC BAY NHI£T KHOA LUAN TOT NGHIEP HE DAI HOC CHINH QUY Nganh Vat Ly lie (Vr Nli;1n Khoa I h)c Tai Nang-Kli6;i 47 Giao \'icn liuong dSn: PGS TS Ta Dinh Canh Giao vien phan bien 1: PGS TS DuThj Xuan Thao Cii;i() \ Kii phaii bien 2: PGS.TS Nguyen Thj Thuc Hien a noi - 2006 Muc luc • • Mfr dau ChiroTig Tong quan ve vat lieu ban ddn ZnO 1.1 Clu true tinh the ZnO 1.1.1 Cau true mang l\ic giae wurtzite ' 1.1.2 Cau true mang lap phuang dan gian ki8u NaCl 1.1.3 Cau true mang lap phuang gia kem kieu sphalerit 1.2 Cau true vung nSng lugng cua ZnO 1.2.1 Cau true vung nang lugng eua mang lue giae wurtzite 1.2.2 Cau true vung nang lugng eua ZnO 1.3 Cae tinh ehat vat ly eua vat lieu ZnO nano 1.3.1 Tinhehcitea 1.3.2 Tinh chat ap dien va cac mat phSng phan cue L3.3 Tinh chat dien 10 L3.4 Tinh chat quang 13 1.3.5 Pha t^p tir 15 1.3.6 Nhan biet cac dial hoa hgc 16 1.4 IJ'ng dung cua vat lieu ZnO Chircng Phuong phap thirc nghiem 17 20 2.1 Phurcmg phap chung de cho tao mlu 20 2.2 Cdc ca ch6 hinh can laic nano 22 2.2.1 Cache hai-i-cln(V-S) 22 2.2.2 Ca cha hai-long-nin (VLS) 24 2.2.3 Ca chi mat phan circ 26 2.2.4 Ca cha l(?ch mang xocln 27 2.3 Ciic phirang pliap phan li' li va ilo di,ic: 28 2.3.1 Plian tich can niic hiing nhieu xa tia X 28 2.3.2 Quan sat hinh thai cau true bang kinh hien vi 29 dien tur quet (SEM) P 2.3.3 Hv ph6 huynh quang va huynh quang kich thich Chiro-ng Ket qua thi,rc nghivm va hicn liuln 30 ^^ 3.1 Qui trinh thuc nghiem: 3.2 Cac dTa va ong nano I6i/v6 ciia kim loai Zn va ban din ZnO 33 3.3 Tinh chat huynh quang ciia cac dia ZnO:In 3^ Ket luan '^^ Tai lieu tham khao 42 %{ t DAI HQC QU6C GIA HA NOI TRCOfNG DAI HQC KHOA HOC TlT NHIEN T r a n Thi Quynh Hoa CHE TAO VA KHAO SAT DAY NANO ZnO C XUC TAC Au BANC PHU'OnVG PHAP BOC BAY NHIET DOTV GIAN LUAN VAN THAC SY KHOA HQC Ctiuyen nganli: Vat ly cftat ran Md so: 60.44.07 Nguo-i hu6nK dan khoa hQc: PGS.TS Ta Dinh Canh Ha Noi - 2006 Mvc Lyc Ua dau Chirffng 1: Tong quan ve vat lieu ZnO 1.1 Cau true tinh the 1.1.1 Cau true mang luai kieu luc giae Wurtzite 1.1.2 Cau true mang luai kieu lap phuang gia kem (Blend) 1.1.3 Cau true mang luai kieu NaCl 1.2 Cau true vung nang lugng cua ZnO 1.3 Mat trang thai 10 1.4 Su lugng tii hoa giam k ich thuoc 10 1.4.1 Su lugng tCr hoa nang lugng giam k ich thu6c 11 1.4.2 Su lugng tu hoa mat trang thai giam kich thuac 13 1.4.3 Dieu kien lugng tu hoa 13 1.5 Mgt so thong so vat ly ciia ZnO 15 1.6 Mgt so tinh chat vat ly dac trung 15 1.6.1 Tinh chat dien 15 1.6.2 Tinh chat ap dien 17 1.6.3 Tinh chit quang 19 1.6.4 Tinh ch§t huynh quang 22 1.6.5 Kha nang nhan biet cac chat hoa hgc 25 Cac phuang phap chi tao ZnO nano 26 1.7.1 Phuang phap top - down 27 1.7.2 Phuang phap boituni - up 27 1.7 1.8 Ca ch8 phat triSn m^u bang phuang phap b6c bay nhiet don gian.29 1.8.1 Cache hai - r5n r 29 r 1.8.2 Cache hai - long - 'an 30 1.8.3 Hien tugrng can bang nhiet dong 30 Chuong 2: Ky thuat thuc iighiun 33 2.1 33 2.2 2.3 C^ie phuang phap c\\c liu^ vat W^w 2.1.1 Sado he boc bay nhiet dan gian 33 1A2, Qui trinh che tao 34 2.1.3 Sado he phijn xa 37 Cac phuang phap nghien ciiu vat lieu 38 2.2.1 Phuang phap nhieu xa ke tia X 38 2.2.2 Phuang phap kinh hien vi dien tir quet 40 2.2.3 He ph6 huynh quang va huynh quang kich thich 42 Xay dyng he khao sal lii* u ung nhay am 43 Chu-ang 3: Ket qua va thao luan 45 3.1 Kit qua phan tich cau tnic 45 3.1.1 Anh huong ciia (y le giira cac vat lieu nguon 45 3.1.2 Anh huang ciia chieu day lap vang tren de 47 3.1.3 Theo nhiet dC 50 3.1.4 Nhan xet ^^ Ph6 huynh quang nhicl Jo lliap eua day ZnO nano 54 3.2 3.2.1 Ca che tai hop iai) \^\\ quang vung kha kien 3.3 54 3.2.2 Ca che tai hop luiynh quang vung tu ngoai 55 3.2.3 Mgt s6 thong so \al ly ^^ Hieu ung nhay 4ni cua ZnO nano 60 DAI HOC QUOC GIA HA HOI TRU6NG DAI HOC KHOA HOC T U N H I E N CAO VAN TUAN CHi^ TAO CAU TRUC NANO ZnO VA ZnO PHA TAP Co BANG PHUONC, PHAP I J C BAY NHlfiT DON GIAN Chuyen nganh: Vat ly cha't vin Maso : 60.44.07 LUAN VAN THAC SI KHOA HOC NGUOl HUONG DAN KHOA HOC: PGS TS: TA DINH CANH Ha Noi -Nam 2006 Muc luc yia dau , :hirongl :T6ng quan ve vat lieu ZnO 1.1 ca'u true tinh the cua ZnO 1.2 ca'u true vClng nang lirgng cLia ZnO 1.3Tinhcha't vat lycija ZnO ca'u true nano 1.3.1 Tinh chat ca hgc g 1.3.2 Hieu ung ap dien va phan circ be mat 1.3.3 Tinh chat dien 11 1.3.4 Tfnh chni quaui; i;^ 1.3.5 Pha tap lir 15 1.3.6 Nhan biet chai hoa hoc 17 1.4 Giam giJi lugng tu' irong nano ZnO 19 1.5 ZnO pha tap 22 1.6 IJ'ng dung cua ZnO 23 huong 2: Phuang phap thuc nghiem che tao va khao sat vat lieu 25 2.1 Phuang phap van chuyen bang pha hai 25 2.2 Ca che phat trien ciia vat lieu cau tnic nano 26 2.2.1 Su phat trien VS 28 2.2.2 Sir phat trien VLS 29 2.2.3 Sir phat then chi phoi bai ca che phan cue be mat 31 2.2.4 Ca che lech mang xoay 34 2.3 Ccic phep phan licli \a dac 2.3.1 Phan tfch cau liiic bang nhilu xa tia X 2.3.2 Quan sat hinh tliai bang kfnh hien vi dien tir quet 35 36 38 2.3.3 Phep hiiynh quang Chirong3 : Ket qua dat dugc va bien luan 38 40 3.1 Qua trinh che' tao mfiu 40 3.2 Suda dang cA'u tnic nano ZnO 41 3.3 Che'lao ca'u true nano ZnO pha tap Co 49 3.4 Anh huorng cac hinh ihuc ca'u true day nano ZnO de'n tinh cha't huynh quang 51 Ket luan 53 Tai heu tham khao 54 PHI^U DANG K t KfiT QUA NGHlfiN CtltJ KH-CN Ten de tai: Kha nSng urng dung cac day nano ZnO dugc che tao bang phuong phap hoc bay nhiet ' Ma so: QT-06-09 Ca quan chu tri de tai: Dai hoc Quoc gia Ha Noi Co quan quan ly de tai: Trufrng Dai hoc Khoa hoc Tir nhien Dla chi: 334 Nguyen TrSi - Thanh Xu^n - Hii nOi Tel: 8588579 Tong kinh phi thirc chi: Trong do: - Tilr ngan sach Nha nirdc: - Kinh phf cua trircVng: 15.000.000 d - Vay iiu (lung: - VOn hrco: - T h u h6i: Th^i gian nghien curu: 01 nam Th6i gian bdt dau: 12/2005 Thoi gian ket thuc: 12/ 2006 Ten cac can bo phoi hop nghien curu: CN, Trdn Tin Quynh Hoa CN Nguyen Viet Tuyen So dang ky de tai So chirng nhan dang ky ket qua nghien cihi: Ngay: Bao mat: a Pho bien rong rai: [x] b Phd bien han che: c Bao mat: Tom tat ket qua nghien curu: + Thiet ke va xay dirng he boc bay nhiet moi truong mang Ar a nhiet -1000^ + Che tao cong day nano ZnO co du^ng kfnh 30-60nm bang cac phuong phap VS va VLS CO chat xiic tac vang + Khao sat tinh chat cau triic, quang va huynh quang cua cac mau tao + Da dao tao cu nhan dai hoc va da dao tao hoc vien cao hoc + Xay dung cong he thuc nghiem su phu thuoc dien tro cua mau vao am cua moi truong + Buoc d^u phat hien hieu ung nhay km cua ZnO, mo kha nang ung dung ZnO nano lam vat lieu sensor tuong lai 21 KKin nghi: NCu d^ tai dugc ca'p thfim kinh phf se khiio sdt tfnh 6n djnh ciia c6ng nghC tao day nan6 ZnO va kha nang urng dung cua ca'u triic nano Chu nhiem di tai Thu truong co quan chu tri tai Chu tjch Hoi dong danh gia chfnh thijrc Thii truong co quan quan ly 66 m T:^KH ^^.^^;.^^'^^^ 22 -> ... images of ZnO nanowires o oo ooo Alloy ciroplcl Au -ZnO o /nO i nanowires Fig 6: Mechanism of the growth of nanowires nanorods As the droplets become supersaturated in Zn and ZnOi.>;, ZnO nanostructures... temperature, etc ZnO nanowires, nanobelts and nanoarrays are the most typical nanostructures Figures 1, 2, show the SEM images of such synthesized nanostructures, respectively Fig SEM image of ZnO nanowires... nano phy thudc vao kich thudc ciia giot chat long va khdng thay ddi sudt qua trinh ch6 tao Hoi Zn vaZnOu, Hoi Zn va ZnO| w O O O, De Si cd phii vang Gigt hgp kim Au - Zn ^ P Day nano, nano ZnO