利用射频磁控溅射法在柔性衬底上制备ZnO_Zr透明导电薄膜_英文_

第24卷　第2期2009年4月液　晶　与　显　示Chinese Jo urnal o f Liquid C rystals and Display sVol .24,No .2Apr .,2009Article ID :1007-2780(2009)02-0183-04Fabrication of ZnO ∶Zr Film Deposited onFlexible Substrate by RF M agnetron SputteringLIU H an -fa ,ZH A NG H ua -fu ,LEI Cheng -xin ,Y U AN Y u -zhen ,Y U A N Chang -kun(School o f Ph ysics and Optic -Electron ic I n formation Technolog y ,S handon g Univer sity o f Technolog y ,Zi bo 255049,China )A bstract :Zirconium -do ped zinc o xide (Z nO ∶Z r )t ransparent co nducting thin films with hig h transmittance ,lo w resistivity and g oo d adhesion w ere firstly prepared o n w ater -coo led poly -ethylene g ly co l terephthalate flexible substrates by RF mag net ron sputte ring .X -ray diffr action a nd scanning elec tron micro sco py sho w that the Z nO ∶Z r film s are polycry stalline with a hexa -g onal st ructure and a prefer red o rientation para llel to the substr ate .T he low est resistivity o b -tained in o ur experime nt is 1.55×10-3Ψ·cm .T he averag e transmittance of the film s is ove r 90%in the w avele ng th range of the visible spect rum .Key words :Z nO ∶Z r films ;flex ible substrates ;mag net ron sputtering ;transpar ent co nductingfilmsCLC number :T N304.2;T N 304.055 Docum ent code :B Received date :2008-09-04;Revis ed date :2008-09-301　Introductio nTransparent conducting thin film s deposited o n flexible substrates have many applications .They are w idely used in flex ible electro -optical devices ,flexible liquid crystal display s ,plastic thin film solar cells ,transparent electrom ag netic shielding materials and unbreakable heat reflec -ting mirrors [1].In recent y ear s ,Sn -doped In 2O 3(I TO )and A l -doped ZnO (ZnO :A l )o n flexible substrates have been ex tensively studied [2-7].But in our know ledge ,no repor t w as published for ZnO ∶Zr film s prepared on flexible substrates up to now .Comparing w ith ITO ,ZnO ∶Zr film s have many advantages of source abundance ,low cost ,innocuity and go od stability (in plasm a ).Com paring w ith ZnO ∶Al ,ZnO ∶Zr films present higher transmittance and better ho t stability .Poly -ethylene g ly co l terephthalate (PET )is a Promising fle xible substrate due to its hig h opti -cal transmittanc e ,high melting point (about 200℃)and lo w chemical reactivity .In this lette r ,we firstly repo rt the preparatio n and prope rties o f ZnO ∶Zr film s depo sited o n w ater -coo led PET substrates by RF m ag netron sputte ring2　ExperimentsZnO ∶Zr film s w ere depo sited on various flexible substrates in a GJP500C2model RF m ag netron sputtering sy stem w ith a basic pres -sure o f 3.4×10-4Pa .A sintered ceramic with a mixture of ZnO (99.99%purity )and ZrO 2(99.99%purity )w ere employ ed as so urce mate -rials .The content of ZrO 2added to the ZnO tar -get w as 5%(mass fraction ).The distance be -tween the substrate and the targ et w as abo ut 50m m .During the proce ss of depo sitio n ,the pres -sure of A r w as co ntrolled at 1.5Pa ,the sputte -ring RF pow er w as m aintained at 100W fo r 40min and the substra te w as w ater -co oled at ro om temperature .U nde r these conditions ,high qua -lity ZnO ∶Zr film s w ith goo d adhesio n ,hig h184　液 晶 与 显 示第23卷transmittance and low resistivity w ere o btained w itho ut damage to the flex ible substrates .The structure and m orpho logy proper ties o f the film s w ere analy zed w ith a D8ADVANCE XRD using CuK α1radiation (λ=0.15406nm )and a Sirio n 200SEM .The optical transmittance m easure -ments w ere pe rfo rm ed with a TU -1901UV -vis spectrophotometers .3　Results and Discussion3.1　X -ray Diffraction AnalysisFig .1show s the X -ray diffractio n spectrum of a typical ZnO ∶Zr film deposited on w ater -cooled PET substrate at room temperature and 100W fo r 40min .The θ-2θscan data of the ZnO ∶Zr film o nly ex hibits a strong peak at 2θ=31.13°,which is very close to the preferred orien -tatio n of the standard ZnO cry stal (31.38°)and corresponding to the (100)peak .This indicates that the ZnO ∶Zr film is po ly cry stalline w ith a hexago nal structure and a preferred orientatio n parallel to the substrate .A previo us study sho wed that the prefer red o rientation for ZnO ∶Zr film s w as dependent o n the expe rimental co n -ditions [8].The full -w idth athalf -m aximum(FWH M )o f the (100)diffractio n peak is calcu -lated as 0.66°,and then the cry stallite size is calculated as 13.9nm according to the Sche rre form ula D =0.89λ/(B cos θ).Thus we can co n -clude that the ZnO ∶Zr film deposited o n PET substrate is nano -structural cry stal.Fig .1　X RD spectrum for a ZnO ∶Zr film deposited o nPET substr ate3.2　SEM AnalysisFig .2show s the scanning electron micro s -co py (SEM )image of a ty pical ZnO ∶Zr film de -posited on w ater -cooled PE T substrate at ro om temperature and 100W for 40min .The ZnO ∶Zr film co nsists of so me flat structural g rains ,re -presenting a prefe rred orientatio n parallel to the substrate ,w hich ag rees w ith the X -ray diffrac -tion (XRD )re sults.Fig .2　S EM imag e of a ZnO ∶Zr film deposited o nPET substr ate3.3　Optical TransmittanceThe optical transmittance as a functio n o f the w av elength fo r the sam e sample o f about 200nm thickness w as measured ,as show n in Fig .3.The average transmittance in the range o f 400～800nm w aveleng th is over 90%.The adhesio n to the substrate for high quality film s w as goo d ,no breakup and fall -off w ere observed w hen the films w ere fo lded many times .Fig .3　Optical transmittance as a function of the wav e -length fo r the same sample3.4　Electrical ResistivityThe electrical resistivity of ZnO ∶Zr film s第2期　LIU Han-fa,et al:Fabrication of ZnO∶Z r Film Deposited o n Flexible Substrate by RF Magnetron Sputtering185deposited o n w ate r-co oled PE T substrates lies o n the expe rimental conditio ns.In o ur experiment, the lowest resistivity ac hieved is1.55×10-3Ψ·cm w ith a thickne ss o f about200nm at the opti-mized co nditions of100W,1.5Pa and40min.4　Co nclusionZnO∶Zr films with high transmittance,low resistivity and go od adhesio n w ere firstly pre-pared on flexible substrate PET by RF magnetro n sputtering.XRD and S EM show that the ZnO∶Zr films are poly cry stalline w ith a hexag onal structure and a prefe rred o rientation parallel to the substrate.The low est resistivity o btained in our expe riment is1.55×10-3Ψ·cm.The ave-rage transmittance of the film is over90%in the w aveleng th rang e of the visible spectrum.This result may be useful for inaugurating the poten-tial applications of ZnO∶Zr film s in flexible de-vices.References:[1]Y ang T L,Z hang D H,M a J,et al.T r ansparent co nducting ZnO∶A l films depo sited o n o rganic substra te s de po si-ted by r.f.mag netr on-sputtering[J].Thin Solid Films,1998,326(1-2):60-62.[2]M a J,Li S Y,Zhao J Q,et al.P reparatio n and proper ties of indium tin ox ide films deposited o n po ly este r sub-strates by reactive evapor ation[J].T hin Solid Films,1997,207(1-2):200-202.[3]M o on C S,H an J G.Lo w tempe rature sy nthesis of I T O thin film on polymer in A r/H2plasma by pulsed DC mag ne-tro n sputtering[J].Thin Solid F ilms,2008,516(19):6560-6564.[4]Li X D,Z hu H B,Chu J B,et al.Indium tin o xide film s prepared by r adio f requency mag ne tro n sputtering under lo wvacuum level[J].Chin.J.L iquid Cry stals and Displays,2007,22(5):553-559.[5]Llaus E,Rainald M.Carrier transpo rt in poly cry stalline IT O and ZnO∶A l II:The influence o f g rain bar rie rs andbounda ries[J].Thin Soli d Films,2008,516(17):5829-5835.[6]F ang G J,Li D J,Yao B L.Influence of po st-deposition annea ling o n the pro per ties o f transpare nt conductive nano-cry sta lline Z AO thin films prepared by RF mag ne tron sputtering with hig hly conductiv e ceramic ta rge t[J].T hin S olid Fi lms,2002,418(2):156-162.[7]Suchea M,Christoulakis S,K atsa rakis N,et al.Co mpa rativ e study of zinc ox ide and aluminum doped zinc o xidetr ansparent thin films g row n by direct cur rent mag net ron sputtering[J].T hin Soli d Fi lms,2007,515(16): 6562-6566.[8]Paul G K,Bandy opadhyay S B,Sen S K,et al.Structural,optical and electrical studies on so l-g el deposited Z rdoped ZnO films[J].Materials Chem.and Phy s.,2003,79(1):71-75.利用射频磁控溅射法在柔性衬底上制备ZnO∶Zr透明导电薄膜刘汉法,张化福,类成新,袁玉珍,袁长坤(山东理工大学物理与光电信息技术学院,山东淄博　255049)摘　要利用射频磁控溅射法首次在室温水冷柔性衬底PE T上制备出了可见光透过率高、电阻率低的掺锆氧化锌(ZnO∶Zr)透明导电薄膜。