DAI HOC QUOC GIÀ HA NOI TRUÒNG DAI HOC KHOA HOC TIJNHIÉN '''' r ''''T T"* T* T'''' ''''1^ lA ^ ^ ^ ^ ^ ^ Tén de tài MÀNG BÀN DAN ZnO, PbS CHE TAO BANG PHUONG PHAP SOL GEL VA TRÀNG GlTONG CÙNG VÓI CÀC DAC TRUNG CI[.]
DAI HOC QUOC GIÀ HA NOI TRUÒNG DAI HOC KHOA HOC TIJNHIÉN ' r 'T T"* T* T' '1^ lA ^ ^ ^ ^ ^ ^ Tén de tài: MÀNG BÀN DAN ZnO, PbS CHE TAO BANG PHUONG PHAP SOL-GEL VA TRÀNG GlTONG CÙNG VĨI CÀC DAC TRUNG CIJA NỊ MA SO: QT-02 12 CHIJ DE TÀI: KHÙC QUANCi DA I DAI HOC QUOC GIÀ HA NĨI TRNG DAI HOC KHOA HOC Tl/NHIÉN Tèn de tài: MÀNG BÀN DAN ZnO, PbS CHE TAO BANG PHUDNG PHÀP SOL-GEL VA TRÀNG GLt)NG CÙNG VĨI CAC DAC TRLING CÙA NỊ MA SO: Q T - - 12 CHL DE TÀI: KHLC QL ANC; DAT CAN BO THAM GIÀ Nguyén Thi Thuc Hien Phùng Quoc Bào iVIai Thi Tàm Ha Nói - 2005 B A O C A O T O i M T À T a Tén de tài: Màng barn ràn ZnO, PbS dicu che bang phiiong phàp sol - g e l va tràng guoiìg vói cac dac trung cùa no IVIàsó: Q T - - 12 b Chù de tài: Khùc Quang Dat e Càn bó thani già: Nguycn Thi Thuc Ilicn Phùng Quóc Bàe^ Mai Thi Tarn d Muc tiéu va nói dung ngliién cùu - Muc ticu: Nghicn ci'ru che lao màng mong hàng phircrng phap sol - gel va tràne eu"cme - Nói dung: - Nghièn ciru che Vdo nnàng ZnO bang phirctng phap sol - gel vói càc dac trirng - Nghicn ciru che lao màng PbS bang phmmg phap Lràng gircmg vai càc dac irung e Càc ket qua dat duoc Dà che tao thành cóng màng ZnO tinh khiél màng / n O co pha lap Al In Dà nghién ciru ành hinVng cùa ciuà ti'ình xiV ly nhicl lói u'nh dinh hitiVng cùa màng ZnO tinh khiét va màng ZnO co pha lap AL In ciing MYÌ càc ifnh chàl quang hoc Da che tao ihành cóng màng PbS, càc yen lo ành hifóng bang phmmg phàp tràng girang - Dà niihién cù'u càc dac trung ve càu irùc, ben nhiéi cùa màng PbS - Càc kel qua nhàn óuac phù ho"p vai càc cịng irình dà cịng bó iren ihc giai va góp phan làm sàng lo va phong phù ihèm phirong phàp che lao màng mòng va càc dac iiung cua càc màng nhàn duoc Vai Cdc kèl qua ihu diro'c chùng lói dà cóng bó' va càc cóng irình khoa hoc sau day: Khùc Quang Dai, Phùng Quóc Bào, Nghuyen Thi l^hiic Hién, Pham Nhguyén Hai, Le Vàn \'ù, Nuuyen Chi Thành Nghién cuu che lao mane ZnO bang phirong phàp sol - gcL Bào cào hói nghi vài ly chàl ràn Knm quoc ihi'r III Nha Trang - 10/8/2001 Phung Quoc Bao, Khuc Quang Dal and Tran Thi Duong Elìcci ol beat ireaiment on ihe slruciural and aplical properiies ol' sol - gel derived ZnO ihin rilms Communicalions in physics, voi 13, No (2003) Pp 10^ HO Phung Quoc Bao, Khuc Quang Dal, Nguycn Thuc llien and Nguyen Ngoc Long Preparalion ni PbS glass ih in lilm by chemiscal haih depc^siiion Communicaliori in physics \'ol.l3 No.3 (2003), pp 171 176 Phung Quoc Bao, Khuc Quang Dal and Nguyen Trong Nghia Sol - gel deposilon o l Z n O : Al ihin Tilms, VNU Journal ol science, Malhemalics Physics T.XIX NoL 2003, pp.l6 - 21 Phung Quang Bao, Khuc quang Dal Nguyen Thien Hui>ng Sol - gel spin coaiing prepareaiion ol Zn(J: jn lilms vviih highly e - axis orienlalion Journal of scicnce, Malhemalics - Physics T.XIX, Noi, 2004, pp - 14 Càc màns diéu che duac co nhiéu dàc ifnh lói c6 ihe une dune cho nhiéu muc di'ch khàc Dira vào de tài dà góp phan vào ihành cóng khóa luan tot nghiép: Le Thi Hoa (Khoa Vài Ly Dai hoc su pham Ha Nói), Ngó Vàn Giang ( Khoa Hoà Dai hoc Quoc già Ha Nói), Ha Vàn Trình, Bùi Thi Thu Hồi, Nguyen Trong NghTa, Nguyen Thi Thién Hirang (Khoa Val Ly Dai hoc Qc già Ha Nc)i) fTình hình su dung kinh phi: Tong kinh phf dirac càp ihirc hien de lai 08 irieu dóng rat khó khan dùng de mua hóa chat dung cu, phàn lich kel qua, ih mitóì nhàn cóng KHOA HOA HOC Uà Nói ngày 16 iliuìv^ 09 nam 2005 CHÙ NHIÈM DF TÀI F Khùc Quang Dat DAIH HOC TCNHIEN OMO witU TOLfÓNG '^GS.T3Mu3^'^Ó M^ DAI OC GIÀ HA NOI ^aìw SLMARV a Reaseaching Project: Studying of preparation of semiconductor membrancs (ZnO, PbS) by sol - gel and chemmical bath de position techniques and it's characteristics CODK:QT-02-12 b Director: Khuc Quang Dat e Members: Phung Quoc Bao Nguyen Thi Thuc Hien Mai Thi Tarn d Reaseaching attitudes and c(~)nlents: Reseaching atlitudes: -Sludy of prepaj-alion oT ZnO ihin lilms by sol - gel melhod and ifs characleritics -Sludy of preparation n( PbS ihin Tilms by chemical baih deposiiion methods and it's characteristics - Reseaching contents: - Preparalions of ZnO, ZnO wiih AL In inpuriiies - Sludy (T ilN characteristics by XRD phoU)luminescence speclra, L'V VIS - Preparalions of PbS by chemical bath deposilions - Sludy ol ifs techniques e Resulls: charactensiics by XRD, TGA, DTA, DSC, SEM, - Thin films of ZnO, ZnO wilh Al In impiuiiies aie sucessfully prepared - Chai-acteristic of thin films of ZnO, ZnO wilh Al, In impuriiies bave becn siudied - PbS ihin films are sucessfully prepared PbS ihin films measuremaenis bave becn siudied by XRD, TGA, DTA, DSC, PHAN NÓI DLNG CHLNH MUC LUC Trang A MÒ DAU B NOI DUNG ^ L Tong qiian: 1.1 Màng ZnO tinh khiét va co pha tap 1.2 Phirang phàp sol - gel che tao màng mòng 1.3 Màng PbS 1.4 Phirong phàp lràng girong che tao màng mòng Ket qua nghién CULI 10 10 2.1 Màng ZnO tinh khiét 10 2.2 VIàng ZnO pha Al 14 2.3 Màng ZnO pha In 14 2.4 Màng PbS 14 2.4.1 Phirong phàp I che tao màng PbS 14 2.4.2 Phirong phàp che tao màng PbS 14 Ket luan 19 C TÀI LIÉU THAM KHAO 20 A MỊ DÀU Màng mịng hien dang dirgc rat nhieu nhà khoa hoc va vài lieu hoc quan làm nbùng irng dung quan cùa chùng Co rat nhièu phiro'ng phap che tao màng mòng Càc phirong phàp vài ly thuàng direte dùng cho càc muc dfch dac hièi, ihich hcTp cho càc muc di'ch nghién culi ca bàn va dang dirgc hồn thién vói ràl nhieu càc ky ihuàl khàc Ben canh dò chùng la co ihé che tao càc màng mòng bang càc phurang phàp hóa hoc va sol - gel Do hoal ifnh ràl linh hoal cùa chùng cho nén rat nhiéu càc nhà khoa hoc cà ITnh virc khoa hoc ca bàn nhir ùng dung quan tàm Trong de tài chùng lói nghién cùu phuang phàp che tao màng mòng dò là: - Che tao màng PbS bang phirang phàp lràng girdng Day phmmg phàp che tao màng mòng rat noi tiéng bang phirang phàp hóa hoc co une dune dàc bici trom: ITnh virc nànu lircvn^ mài irai - Che tao màng ZnO bang ky thuàl sol - gel Là mól ky ihuàl circ ky thuàn lién cho càc nhà vài liéii hoc phàl hien nhùng dac ifnh meri la nghién ciru va ùng dung ve dién, ur, quang hoc Mòt so yeu tó quan irong ành hirịng den dàc tfnh cùa màng mịng vói nhiéu dàc tfnh ve tinh the, huynh quang, dò ben nhiéU dirac nghién ciru irong de tài Càc kèl qua dà diroc còng bị tién nhiéu cịng tiình tai càc hịi nghi khoa hoc vài lièu nhir càc lap chi khoa hoc B NOI DUNG Tòng quan 1.1 Màng ZnO tinh khié't va co pha tap Trong nhùng nam gàn day ZnO lai duoc chiì y nghién cim manh me nhàm l'rng dung ITnh vuc quang dién tir, nhir làm eira so cho pin mat tròi, man hién thi nhiìng iru the noi bai cùa ZnO so vói càc vàt liéu khàc nhir dị rịng vùng càm lón (E^~3.3eV ònhiét dò phòng), nang lirong lién kéi cxction lón (60 meV) Co the pha tap Al In de cài thién càc tinh chat dién lù cùa mane L2 Phirang phàp sol - gel che lao màng mòng Co nhiéu phircmg phàp lao màng lù vài liéu này, \i du phircmg phàp phun iTnh dién phùn xa, làng dong bang xung laser Tuy nhién phiro'ng phàp sol - gel co mịi uu diém han so vói càc phircrng phàp khàc khà dan giàn, iicn lai va kinh te vi khóng phài dùng thié't bi tịt, qua dal va dèi hịi càc che dị nghiém ngàl nhu chàn khóng cao nhiét cao Phirang phàp cho phép tao màng ị nhiét dị ihàp bang phàn ùng hóa hoc cùa càc chàl hùu ca chùa Zn Tuy nhién, chat lirang cùa màng hién lai khóng ihe dal den dị hoàn hào nhu nhùng màng tao bang càc phuang phàp epilaxi, spullering Sau tao gel chat Itrang cùa màng phu ihc vào nhiét dị ù Tìm duac che lòi uu va xem xet sir òn dinh cùa màng mot nhiém vu quan cùa cóng nghé Trong bào cào chùng lói trình bay càc ket qua bucTc dàu vice nehién cùu che tao màng ZnO khóng pha tap làm cùa so quang hoc bang phirang phàp sol - gel tu hgp chat Zn(CH3COO) 2H,0 • DAI noe QC GIÀ NĨI TRNG DA! HOC KHOA HOC TUNHIÉN KHOA VÀTLY Ngiiyóii Ihicii Hiroiiy NCnnÈN CIJIJ VA ( H E TAO MÀN(; Zn():In HÀNCÌ PHllONG PHÀPSOL-C.LL K I I O À I U A N l Ó T NCillIPP I I R O A I H O C X l l f N H Q U Y Ngành Quang luang (ù Càn bò hirang clan : l's Phùng Qc Bào Khiìc Quang l)al Ha Nói -2003 COMMUNICATIONS IN PHYSICS Published by NATIONAL CENTRE FOR NATURAL SCIENCE AND TECHNOLOGY OF VIETNAM Volume 13, Number June 2003 Contents Page P B Thakor, P N Gajjar and A R Jani - Structure of liquid alkali metais - A model potential application Hoang Ngoc L o n g , Dang Van Soa and Dinh Phan Khoi - Review of the minimal SU{3)f-®SU{3)^®U{ì)^ 65-72 73-80 model and production of single charged bilepton in e y collisions Vu Dinh lam, Le Van Hong and Phan Hong Khoi - Development and regression of the norma! state zone in YBCO thin films bridges 81-85 Do Phuong Lien and Pasturel Alain - Systcmanc study of atomic structures of MIx^Vx ( MT=Fe Mn, Ni, Cu) amorphous alloys by molecular dvnamic simulalions 86-92 Tran Quoc Viet, Thai Van Lan, Hoang Xuan Nguyen and Pham Van Hoi - Measurement of the cross-talk and inserì losses of array-waveguided-grating (AWG) optical sv^iches Dao Van T r u o n g , Than Due Hien, Nguyen Khac Man, Nguyen Due Minh and Nguyen Hanh - Synthesis oi Bi{Pb)-2223 superconductor by citrate sol-gel method P h u n g Quoc Bao, Khuc Quang Dat and Tran Thi Duong - Effect of heat treatment on the structural and optical properlies of sol-gel-derived ZnO thin films Tran Due Thiep Nguyen Ngoc Son, Truong Thi An, Phan Viet Cuong and Nguyen The Vinh - Calculation of the nuclear leve! density tn photonuclear reactions vMth the shell and pairing structure correction Lue Huy H o a n g , Nguyen The Khoi, Nguyen Van Minh, Nguyen Van Hung and Vu Xuan Q u a n g - Raman polarization studies of Vietnamese spine! MgAljO^ 93-98 10 Tran Dai Nghiep and K h u o n g Thanh Tuan - Investigation of positron annihilation rate in aluminium samples 99-104 105-110 111-117 118-123 124^128 COMMUNICATIONS IN PHYSICS Editor in Chief: DAO VONG DUC Editorial Board Nguyen Xuan Chanh Nguyen Chau Tran Ba Chu Nguycn Van Do Dao Vong Due Nguyen Van Den Nguycn Ngoc Giao 10 11 12 13 Pham Duy Hien Nguyen Van Hieu Le Van Hong Nguycn Dai Hung Phan Hong Khoi Nguycn Ngoc Long 14 15 16 17 18 Hoang Xuan Nguyen Tran Huu Phat Nguyen Xuan Phuc Nguycn Toan Tliang Pham Van Tliieu Hanoi University of Technology College of Naturai Sciences, Hanoi National University Institute of Applied Physics Institule of Physics, NCST Institute of Physics, NCST College of Naturai Sciences, Ho Chi Minh City National University College of Naturai Sciences, Ho Chi Minh City National University Vietnam Atomic Energy Commission Institute of Materials Science, NCST Institute of Materials Science, NCST Institute of Physics, NCST Institute of Materials Science, NCST College of Naturai Sciences, Hanoi National University Institute of Physics, NCST Vietnam Atomic Energy Commission Institute of Materials Science NCST Institute of Physics, NCST Institute of Physics, NCST (Scientific Secretary) Managing Secretary: Nguyen Xuan Giao Address of Editorial Office: 70 Tran Hung Dao Str, Hanoi - Vietnam Tel: 04 - 9.422825 Email: Phi-com(aisi.ac.vn Communications in Physics, Voi 13, No (2003), pp 105-110 E F F E C T OF HEAT TREATMENT ON THE STRUCTURAL AND OPTICAL PROPERTIES OF SOL-GEL-DERIVED ZnO THIN FILMS PHUNG QUOC BAO, KHUC QUANG DAT, AND TRAN THI DUONG College of Naturai Sciences, Hanoi National University A b s t r a c t The structural optical properties of ZnO thin films prepared from zine acetate dihydrate in ethylenc glycol solution by the sol-gel spin-coating technique on silicium substrates have been investigated together with the effects of post-deposition heat treatment in air Increasing the post-annealing temperature in the range of 200^C to 520''C improved the film crystallite quality Highly c-axis orientation was mostly announced for the films post-annealed at 520"C The considered heat treatment did not affect strongly to the films' UV-Vis absorption spectra With increasing the post-annealing temperature, the excitonic photoluniiriescence band was enhanced while the green one hardly changed I INTRODUCTION Zine oxide (ZnO) films contirme to be technologically important due to thcir high optical transmission and elcctrical conduction, which mako thcm suitable for a variety of applications sudi as transparent conductors [l], gas sensors [2], etc ZuO thin films have been prepared by many deposition methods: thermal evaporation [3], charged liciuid cluster beam (CLCB) [4], spray pyrolysis [5] D C / R F magnetron sputtering [6,7], pulsed laser ablation [8], molecular beam epitaxi (MBE) [9] and sol-gel process [10] Sol-gel process is qiiite simple, no ncvd using sophisticated expensive eciuipment and easv to prepare ZnO thin films at low cost for scientifico-tcchnological purposes Thin films can bo derived by the reaction betweon Zn-contained organic substances However, the as-obtained fihn's quality is not as pcrfoct as those deposited by sputtering and MBE techniques Once gel fornied, tlir lilnfs quality stronf^Iy depends on the anncaling temperature To work out the optimal heat treatment and to study the film stability are of great importance for this deposition method In o-eneral, the metal alkoxides have been used as raw materials for the sol-gel process But the preparation of a stable sol is tedious and metal alkoxides' reagents 106 PHUNG QUOC BAO, KHUC QUANG DAT, AND TRAN THI DUONG are very expensive Therefore, instead of metal alkoxides, some metal salts such as acetate, nitrate are used for preparing thin films Zine acetate, which is inexpensive and easy to handle, has been used as raw material in chemical vapour deposition (CVD), spray pyrolysis and atomic epitaxy methods In this paper, w^e report on the preparation of ZnO thin films from zine acetate dihydrate in ethylene glycol solution by the sol-gel spin-coating process It is known that the deposition process governs the micro-structure and the properties of this material The aim of this w^ork is to investigate the influence of the post-heat treatment on the structural, optical properties of the as-deposited ZnO thin films II E X P E R I M E N T A L P R O C E D U R E Fig shows the flow chart of the ZnO films' preparation steps Zine acetate dihydrate solutions (of 0.1 - 0.5M) in ethylene glycol stabilized by triethylamine were used Clean siUcium sHdes were used for the chemical sol-gel depositions A solution of zine acetate dihydrate, Zn(CH3COO)2.2H20, was prepared in pure ethylene glycol The mixture was heated in a condenser-fitted round-bottom flask to I05^C under magnetic stirring for h to yield a clear and homogeneous solution The as-prepared solution was then properly adjusted with triethylamine drop by drop to assist hydrolysis of zine acetate After carefully mixing and ultrasonication, the resulting solution was coloress and transparent The precursor solution was spun on silicium substrates by spin- coating method The spinner operated at 2500 rpm in the environment of 90% relative humidity and room temperature The wet films were preserved for a period of time (about 15 hours), then pre-fired in air atmosphere wnth a heating rate of about F C / m i n up to 200''C The spin coating was repeated several times keeping the films visually transparent Afterwards the films were heat C,H,0 2n(CH,C00j 2H,0 Slimng al ca 105'C Clcdr vliJi(T> TnclhvUniDie Shalong & Ullnisonicjliai Spiri cojling Rcp&jlìng Drvffig in in I5>i (a Hcating •ilow.iy up lo 520 X 2rC* dmsc Tilm Fig Flow chart of the ZnO film coating steps EFFECT OF HEAT TREATMENT ON THE STRUCTURAL AND OPTICAL 107 annealed in air atmosphere to convert the organic coatings containing Zn^^ into its respective oxide A heat ramp of 20^C/min was used and the samples were kept m the furnace until coohng to room temperature XRD measurements were carried out on a Bruker X-ray diffractometer D5005 operated at 40 kV, 20 niA, using CuKa radiation Absorption spectra were recorded by a Shimadzu UV 3101 spectrophotometer Photoluminescence spectra were measured by Jobin-Yvon FL 3-22 fluorometer with 2nm resolution III RESULTS A N D DISCUSSION Fig shows the XRD patterns of ZnO thin films post-annealed at various temperatures One can see some typical diflPraction peaks originated from wurtzite polycrystalline ZnO without any strange phases High-intensity [002] peak was observed in ali measured XRD patterns The lOO^C-annealed film gives quite weak XRD peaks Increasing the anneaUng temperature in the range of 200^^0 to 500*^C made diffraction peaks stronger, which showed the improvement of crystallite quality For ZnO films annealed at more than 550^0, the quality became worse due to substrate deformation With increasing annealing temperatures, the c-axis orientation gets stronger, as well as the ZnO crystallite size larger The strongest c-axis orientation occurs at about 5200 C However, the full width at half-maxima (FWHM) of the (002) peaks was hardly changed with increasing film annealing temperature Therefore, the multiple layer coating was considered not to disturb the overall giowth of the films with c-axis orientation A typical sample of sol-gel deposited ZnO thin films post-annealed in air at 520^^0 were optically characterized through near UV-Vis (200-800 nm) absorption measurements The average transmission over the 400-800 nm range is about 87% There is a band edge absorption around 380 nm The calculated optical band-gap is very dose to the intrinsic band-gap of ZnO (3.2 eV) The photoluminescence excitation wavelength used was 325 nm The as-excitcd photoluminescence spectrum consists of the excitonic band centered at ca 380 nm 'Uid the characteristic green emission at ca 500 nm Excitonic photoluminescence i> very sensitive to the quahty of crystal structures and to the presencc of dofects Tlu^ more perfect is the crystal, the more probable is the observation of free-exciton photoluminescence [11] As reported in [12], the oxygen vacancy causes a green *^*niission band in ZnO 108 PHUNG QUOC BAO, KHUC QUANG DAT, AND TRAN THI DUONG 120 110 100 ^ 90 S 80 U 70 ^ 60 50 40 30 20 10 a/ ]!MAM\I,Ì^^ A:!^i MjYK ^/^vVAV'^f4 50 40 30 2-Thela-Scale 120 110 100 90 ^ 80 U 70 e 60 50 40 30 20 :/Y•v^M/lAVW^^^^^ 10 30 b/ >\\rf\^*fw>^ 50 40 2-Theta-Scale 130 :• 120 : no d 100 90 80 70 60 50 40 o oo 20 hhl^^^i\^^,yM ^^V^AA^/vW^v-v/p^^ 30 F i g 2,XRD 40 2-Tlieia-ScaJe 50 patterns of the as-deposited ZnO films post-annealed in air at 220^0 (a); 400^^0 (b), and 520^C (e) Fig showns the photoluminescence spectra of ZnO films post-annealed at various temperatures The excitonic photoluminescence band was observed and got EFFECT OF HEAT TREATMENT ON THE STRUCTURAL AND OPTICAL 109 more and more intense with increasing the post-anneahng temperature Because other deposition conditions were fixed, the enhancement of excitonic photoluminescence may be attributed only to the heat treatment temperature As for the green emissions, they were almost similar to each other This means that the post heat-treatment in air not make a significant change in the oxygen percentage in the films e/; U 450 500 Wavelength (nm) Fig Photoluminescence spectra of the ZnO films post-annealed in air at 220^0 (a); 300"C (b); 400^C (e) and 520^C (d) As reported in [13], the sol-gel-derived Al-doped ZnO thin films deposited in the same heat treatment conditions display a narrower excitonic photoluminescence band and a larger and more intense photoluminescence green band IV C O N C L U S I O N ZnO thin films were fabricated by the sol-gel spin-coating method Their structural and optical properties were investigated with allowance for various postdeposition heat treatment temperatures The XRD analysis showed that the highly c-axis orientation of crystallites had been more and more announced with increasing the film anneahng temperature up to 520^0 This result might be attributed to the good crystallization due to the relatively high annealing temperature for the formation of ZnO The UV-Vis absorption edge suffered a very small change under the same consideration The estimated optical band-gap was comparable to those obtained for undoped ZnO films deposited by other techniques The variation in photoluminescence spectra with annealing temperature was clearly exhibited On no PHUNG QUOC BAO KHUC QUANG DAT, AND TRAN THI DUONG annealing in air up to 520^*0, the exciton PL centered around 375 nm was observed with increasing intensity, w^hile the green band centered at ca 502 nm was almost unchanged This might be explained by the non-enhanced density of oxygen vacancies in as-treated ZnO films REFERENCES 10 11 12 M Purica et ai, Thin Solid films, 383 (2001) 284-286 K S Weissenrieder, J Muller, Thin Solid Films, 300 (1997) 30-41 M Jin et ai, Thin Solid Films, 357 (1999) 98-101 M Koyano P Q Bao et Phys Stai Soi (a), 193, No.l (2002) 125-131 K H Yoon J Y Cho Materials Research Bulletiv, 35 (2000) 39-46 M Chen et ai, Materials Letters, 48 (2001) 194-198 D H Zhang et ai, Materials Chem and Phys., 68 (2001) 233-238 K L Narasimhan et ai, Thin Solid Films, 295 (1997) 104-106 Y Chen et ai, Materials Sci and Eng., B75 (2000) 190-198 T Schuler, M A Aegerter, Thin Solid Films, 312 (1998) 37-39 T V Butkhuzi et ai, Phys Rev., B 58 No 16 (1998) 10692-10695 F H Lcitcr et ai, Phys Stat Soi (h), 226, No.l, (2001) R4-R5 13 P Q Bao et ai, J Sci., VNU, to be published Received 15 Febrvary 2003 GUIDELINES FOR CONTRIBUTORS The object of "Communications in Physics" is the publication of new theoretical and experimental research works in ali fields of physics Each volume contains issues, which are published quarterly The manuscripts should be submitted in duplicate to the Editorial Board or to any Editor The selected papers must have not been submitted for the publication to other joumals The manuscript, which includes an abstract of not more than 100 words, references, tables, figures and figure captions should be clearly typed in English on ordinary A4 size paper Type only on one side of the typing sheets with ampie margins at the size, top and bottom of the page Each page of the manuscript should be numbered at the top The text must be typed legibly Each symbol must be clear, either typed neatly or written in ink and properly aligned to distinguish superscripts and subscripts Tables and figures are also numbered in the order, in which they are cited in the text Each table and each figure should occupy a separate page, and they should be large enough for reduction to a minimum of 50% of their originai size At the bottom of each figure the names of authors, the title of the paper and figure number should be clearly t>^ed A list of figure captions should be given on separate sheet Footnotes and references should be listed separately at the end of the text The preferred format of the references is indicated below: J G Bednorz, and K A Muller, Z Phys B64 (1986) 185 The author's name, address and institution should be given The badly arranged manuscripts are returned PRINTED AT PRINTING WORKSHOP OF Vietnam Central Fine Art Company ^ HOC QUOC GIÀ HA NOI TNAM NATIONAL UNIVERSITY, HANOI ISSN a S È - JOURNAL T O A I i - VAT LY M A T H E M A T I C S - PHYSICS T XK, Noi, 20tfllÌ •V- ••"^I_' V-; S O L - G E L D E P O S I T I O N O F ZnOiAl T H I N F I L M S P h u n g Quoc B a o , K h u c Q u a n g Dat a n d Nguyen T r o n g N g h i a College of Science, VWf/ tract Smglelayer aluminium-doped zine oxide fiJms were prepared on um substrates by the sol-gel spin coating process The as-deposited fUms j been characterized by X-ray diffraction (XRD) and optical spectroscopy AH ics were polycrv'sialliDe wiih ihe hcxa^onai sinjciure and the prcfered [002] lexture iy c-axis oneoted 2nO;AI ihin films were obtained by annealing at 520°C The films >!t an average UV-Vis iransmiilance of SVCc The iwo 325nm-exciied PL bands were )bser%'ed al room temperature duction oxide films and their doped forms are being extensively studied and ed in various fields due to their high visible transmittance and low DC These materials- hdve gi'eat potential for applications in solar cells [1,2] lanel display electrodes [3] A variety of deposition techniques has been )r fabricating doped and undoped ZnO thin films, such as pulsed laser 1] sputtering [5.6], evaporating [7], spray pyrolysis [8] and sol-gel process ter, we reported the preparation of ZnO thin films by the sol-gel spin 'ocess from zine acetate in ethylene glycol solution Compared to ZnO doped ones have lower resistivity and better stability Furthermore, ms show comparable electrical and optical properties with those of Sn)3 films (ITO) - the predominant transparent conductive oxide films [11] is paper, the structural, optical properties of ZnO:Al t h m films prepared ove-mentioned technique from zine acetate dihydrate and aluminium ethylene glycol solution have been investigated together with the effects losition treatm.ent :n air imental details aration of films [i-C00)'>.2H:0 was first dissolved in an ethylene glycol solution at room -e The r e s u l t a n t solution was stirred at ca lOó^'C m a condenser - fitted hour to \'ield a clear and homogeneous solution Al(X03)3.9HoO was the similar procedure ^^•as carried out The ,Al:Zn atoms ratio in on in this paper was 0.1 at°o optimally obtained from experimental data ution ^vas kept hermetically for - rìays before coating- Silicium slides 16 Sol'^'el deposition of ZnO:Al thin films 17 were cleaned by appropriate solvents The coating solution was prepared by adding several drops of triethylamine to mi of t h e sol solution, shaking and ultrasonication Thin films of ZnO:Al were prepared by the spin coating technique The deposition solution was dropped on the glass substrate and spun at 2500 rpm for 30s After coating, t h e precursor films were kept in humid air for 15 hours to facilitate hydrolysis The films were then slowly heated to the desired high t e m p e r a t u r e and annealed for hours to desorb solvents from the sample and to transform t h e adsorbed zine complex into zine oxide The as-prepared films were highly t r a n s p a r e n t without any cracks Fig shows the flow chart of the preparation of t h e ZnO:Al films Tải FULL (86 trang): https://bit.ly/3UuBt7d Dự phịng: fb.com/TaiHo123doc.net fi • t QH,0, Zn(CH3COO)2.2H20 Al(N03)3.9HiO Stirring atca.l05°C Clear solution Tncthvlaminc Shaking & Ullrasonicalion Spin coating Rcpcating Drying m air for 15h Hcating slowh un IO 520 =C ZnOAl film l-ii^ I Mow chart of the ZnO;Al film coating steps Phung Quoc Bao, Khuc Quang Dat, Nguyen Trong 18 Characterization Nghia of films ,fl The structural properties of the obtained films were analysed by a Bruker Sieme*hs D5005 X-ray diffractometer using CuKe performed at grazing incidence (9 = 2°) The crystallite size was calculated from the FWHM of the ^(002) peak corrected for the instrumentai linewidth broadening using the Sherrer formula Optical transmittance and UV-Vis-near IR absorption spectra were measured using a Shimadzu UV3101 double-beam spectrophotometer Photoluminescence spectra were recorded by a Jobin Yvon F322 fluorometer Resuits and d i s c u s s i o n Structure Tải FULL (86 trang): https://bit.ly/3UuBt7d Dự phòng: fb.com/TaiHo123doc.net properties X-ray diffraction (XRD) was employed to determine the crystal structure of the as-deposited films After the deposition, the films were dried in air That made some weakly adsorbed compounds desorb from the films Fig 2a shows the XRD pattern of such a film The ethylene glycol was totally desorbed without affecting the zine complex Zine acetate dihydrate in ethylene glycol was transformed into zine monoacetate Zn(C2H302) adsorbing on the substrate The films crystallized in a monoclinic crystal structure with a strong orientation in (100) direction, corresponding to zine monoacetate F^r«2 Fig XRD patterns of the as-deposited ZnO:Al films: a) dried in air for 15h; b) post-annealed in air at 520*^0 for 3h Sol'gel deposition ofZnO:Al thin films 19 After annealing at 400°C the (100) reflection of the monoclinic structure dissappeared, t h e zincite hexagonal structure of ZnO was formed By increasing the annealing t e m p e r a t u r e , the preferential orientation of the crystallites were more and more announced Finally, at 520^0, the only very sharp (002) peak was observed in the XRD p a t t e r n (Fig 2b) The highly c-axis oriented crystallites were t h e n produced The (002) peak location was at 29 = 34.48°, very d o s e to t h a t of the standard ZnO crystal (34.45°) This implies that aluminium replaces zine substitutionally in t h e hexagonal lattice > As shown in Fig 2, with increasing post-deposition heat treatment t e m p e r a t u r e , the locations of the recorded diffraction peaks not change significantly, while their intensities become more intense confirming the improved crystallinity and t h e larger average gi'ain size Optical properties " _ The al»iminium-doped ZnO thin films were optically characterized through Lransmittance m e a s u r e m e n t s in the near UV-Vis Fig shows the optical t r a n s m i t t a n c e spectrum for a typical sample of sol-gel synthesized ZnOiAl thin films annealed in air at 520°C The average transmission over the 400-800 nm range is about 87% There is a sharp increase intensity of t r a n s m i t t e d light around 380 nm due to band edge absorption The band gap of Z n O A l calculated from the s t r a i g h t part of the optical transmittance spectrum is closf* to the intrinsic bandgap of ZnO (3.2 eV) F^urtS / ; Fig UV-Vis transmittance spectrum of the ZnOAl films post-annealed in air at 520'Cfor3h 6837051