Ceramic Processing Research

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1 Junal f Ceamic Pcessing Reseach. Vl. 9, N. 4, pp. 416~40 (008) J O U R N A L O F Ceamic Pcessing Reseach Pepaatin f silve Nan-Cystal pattens in xide glasses unde electic field accmpanied by heat teatment Jian Lin*, Wen-Hai Huang, Shu-Hua Lei, Chang-Cheng Liu, Qi Bian, Li-Na Ma and Dng-Wei Li Cllege f Mateials Science and Engineeing, Tngji Univesity, Shanghai 0009, China Nan-cystals embedded in glass always have inteesting quantum effects, while nan-cystal pattens may have wide ptential applicatins in pepaing PIC, OEIC and the types f electnic and ptelectnic devices. A diect cuent electic field, accmpanied by heat teatment, was applied n telluite silicate glass sheets. The silve ins in a diffused film wee intduced int the glass matix unde a high-vltage electic field, instead f supplied duing glass melting. The diect diffusin f metal ins, the nucleatin and cystallizatin f nan-cystals in the glass wee well cntlled by the electic field accmpanied by heat teatment. It was fund that silve nan-cystal pattens can be tansfe pinted int telluite and silicate glass sheets with bth pattened diffusin and pattened cystallizatin. Key wds: Nan-cystal, Patten, lass, Electic field, Tansfe pint. Intductin Nan-cystal embedded glasses have many exciting ptical ppeties such as luminescence and nnlinea ptical pefmance [1-5], which ae much bette than a glass matix and cystals by themselves. When the nan-cystals embedded in the glass substate ae aanged in the desied pattens, the nan-cystal pattens will have a ptential applicatin in phtnic integated cicuits (PIC), ptelectnic integated cicuits (OEIC) and the types f ptelectnic devices. Nwadays, a vaiety f nanpatten pcesses, such as electn beam lithgaphy, X-ay lithgaphy, exteme ulta vilet lithgaphy and nanimpint lithgaphy, have aleady been used in pducing IC chips [6-9]. The types f nan-pattens with 100 nm in line width and less, can be pepaed by these pcesses, but it is still difficult t pepae IC OEIC chips with nan-cystal pattens. S, it is useful t find a new pcess t pepae nan-cystal pattens in glass substates. Nan-cystal embedded glasses can be pepaed by a heat teatment pcess, a pus glass pcess, sl-gel methds, an in exchange pcess etc. [10-1]. Sme extenal fields, such as electic, magnetic and ptic fields wee als epted t be applied t cntl the nucleatin and cystallizatin f nan-cystals [13-15]. It is imptant t cntl the gwth f nan-cystals in the desied lcal aeas when pepaing nan-cystal pattens in glass substates. Tw methds can be adpted t cntl the pattened distibutin f nan-cystals in a glass substate, ne is t cntl nucleatin and cystallizatin f the glass in a lcal aea *Cespnding auth: Tel : Fax: lin_jian@mail.tngji.edu.cn unde a DC electic field [16], the the is t nly intduce pecusive metal ins int the desied aeas f the glass substate and then sepaate nan-cystals in these aeas. In this study, a heat teatment pcess accmpanied by a DC electic field was epted t bth lcal-aea implant pecusive metal ins int glass substates and cntl the nucleatin and cystallizatin f nan-cystal pattens in telluite and silicate glass sheets. Expeimental The TeO -Nb O 5 -BaO glasses wee pepaed using ptical gade mateials. Optical gade AgCl was intduced additinally fm 0 t 4 wt%. The well-mixed batches f cystalline mateials wee melted at C f 10-0 minutes in a gld cucible. The melt was cast n t a steel plate and annealed at C f h, and then cled slwly t m tempeatue in the funace. The glass samples wee cut t a size f 0 mm 0 mm 1.5 mm and then plished. Als, cmmecial silicate micscpe slides with a thickness f 1-1. mm wee als used in the expeiments. A pattened silve film was pinted nt the glass sheets using BYJ0775 silve paste, was pepaed by magnetn sputteing. The glass sheet was pcessed in a heat teatment appaatus accmpanied by an auxiliay electic field, which is shwn schematically in Fig. 1. The glass sheets wee heat teated at C f minutes, while a Au electde was used t lad the DC electic field with V/mm at the same time. The tansmittance f patten tansfe-pinted glass sheets was studied by CRT760 UV-VIS spectphtmete. The nan-cystals embedded in the glass wee bseved by a Quanta 00FE Field Emissin SEM. 416

2 Pepaatin f silve Nan-Cystal pattens in xide glasses unde electic field accmpanied by heat teatment 417 Fig. 1. A sketch diagam f nan-cystal patten tansfe pinting. Results and Discussin Intductin f Ag ins int glass substates Befe silve nan-cystals wee fmed in the glass substates, Ag ins must be intduced int glass as pecusive ins f silve nan-cystals. The Ag ins can be intduced int glass substates when melting the glass, and they can als be intduced by in exchanging in implanting afte melting. It was fund that the Ag ins can be intduced int glass sheet diven by a lcal-aea applied extenal field [16], this makes it pssible t btain the nan-cystals in the desied lcal aeas and fm nancystal pattens in the glass sheet. The Ag ins can be intduced by diffusing int glass sheets unde a DC electic field. When the silve film was cated n the suface f glass sheet, the Ag ins in the film will diffuse int the glass sheet diven by the cncentatin gadient between the silve film and the glass substate. The themal diffusin f Ag ins will als exist in the glass in a andm way. When a DC electic field is applied nt the glass sheet, the diffusin diven by the electic field induces Ag ins diffusing int the glass sheet alng the electic field line. Theefe, the diffusin f Ag ins unde an electic field includes andm themal diffusin, cncentatin gadient diffusin and highly diected electic field induced diffusin. If the teatment tempeatue f the glass sheet is unifm, the themal diffusin can be neglected. S, the diffusin fce f Ag ins int glass sheet includes the fce fm the electic field F E and the fce fm the cncentatin gadient F C : F E = qe F C = KT ln γ () ln x whee q is the quantity f diffusing ins, E is the intensity f the electic field, T is the teatment tempeatue, K is Bltzmann s cnstant, γ is the activity cefficient, and x is the diffusin distance. Accding t Fick s fist law, the diffusin flux f metal ins in the x diectin, which is pependicula t the glass sheet, J is: J D C D qec C qec D Q = = exp (3) x KT x KT RT C S, D C qe = C t x KT x (1) C = D qe C Q exp (4) x KT x RT whee C is the cntent f metal ins, D is the diffusin cefficient, D 0 is the fequency fact, and Q is diffusin activatin enegy. In additin t the stuctue and pefmance f the glass substate and the sepaate cystals, the diffusin f metal ins is als affected by the electic field intensity, the cncentatin gadient, the teatment tempeatue and time. When the glass sheet is at a lwe tempeatue, the diffusin f the metal ins is mainly cntlled by the DC electic field, and the diffusin due t the cncentatin gadient is smalle. The ins will be implanted int the glass sheet mainly alng the electic field line. When the teatment tempeatue is inceased, the diffusin due t the cncentatin gadient will incease gadually, it will diffuse metal ins nt nly fm the tansfe pinting film t glass substate, but fm metal-in-cntaining aeas t metal-in-fee aeas, which esults in nan-cystal pattens which ae ut f fcus. Theefe, it is imptant t decease teatment tempeatue as fa as pssible t estain the cncentatin gadient induced diffusin, and incease the electic field induced diffusin. If the Ag ins wee intduced when melting the glass, these ins ccupy sme psitins in the glass netwk and ae in a stable state. By cntast, when the Ag ins ae implanted unde an electic field, the slidified glass stuctue is difficult t expand t accept new ins. Theefe, the implanted Ag ins have t wedge int naw intestitial psitins in the glass netwk with a cmpessive stess. When the Ag -in implanted glass is heat teated, the nucleating and cystallizing tempeatue f the nan-cystals will be deceased by the stess, and the size will als be deceased because f difficult Ag -in diffusin in the dense glass stuctue. FESEM pattens f silve nan-cystals in nibic telluite glasses ae shwn in Fig.. When the % AgCl cntaining glass was annealed at 360 C, which was aleady nea its sftening pint, the aveage size f nan-paticles in the glass was abut 30 nm (Fig. a). When the Ag ins wee implanted by using an electic field, the cystallizing tempeatue was deceased t 30 C, and the aveage size f nan-paticles was als deceased t abut 0 nm (Fig. b). The nan-paticles etained thei small size n the glass suface, even when the quantity f paticles was much me than that in the css sectin f Ag implanted glass and AgCl cntaining glass (Fig. c). Nucleatin and cystallizatin f silve nan-cystals in the glass substates lasses ae a type f metastable mateials which ae stable dynamically but unstable themdynamically. They will nucleate and then cystallize when the heat teatment pvided can vecme the phase tansitin ptential baie. If an auxiliay DC electic field is applied t a glass sheet accmpanied by heat teatment, the influence

3 418 Jian Lin, Wen-Hai Huang, Shu-Hua Lei, Chang-Cheng Liu, Qi Bian, Li-Na Ma and Dng-Wei Li f the electic field n the phase tansfmatin f the glass must be cnsideed. The fee enegy change Δ f nucleatin is seen as Eq. 5 [13]: 4 3 Δ = Δ V Δ S Δ E = ---π 3 1 (5) Δ V ---(ε ε1) 4π σ whee Δ V is the stain enegy pe unit vlume, Δ S is the suface fee enegy change, and Δ E is the fee enegy change due t the electic field. is the adius f a nucleus, σ is the effective suface fee enegy pe unit aea. ε and ε ae the dielectic cnstants f the glass and cystals, is the intensity f the electic field. If the dielectic cnstant f the glass is less than that f the cespnding cystal, the auxiliay electic field will acceleate nucleatin and cystallizatin f the glass. It will play a estaining effect thewise [13]. Heat teatment is ne f the mst cmmnly used steps t stimulate gwing nan-cystals fm a glass. The silve nan-cystalline paticles wee sepaated ut fm the Ag diffused nibic telluite glass sheet when heat teated at C. They culd als be sepaated ut fm silicate micscpy slides when heat teated at C. The pcess f Ag ins diffusin and the silve nan-cystal paticles gwth culd be meged int ne step when a teatment tempeatue is available. F example, the tw pcesses ccued at the same time when the teating tempeatue f nibic telluite glasses was fm C. The cystallizatin tempeatue f silve nan-cystals in silicate glasses is always me than 450 C, a bette chice f these types f glasses was t diffuse Ag ins at C at fist, and then e-anneal at C t btain nan-cystals. The influence f teatment tempeatue n the tansmittance f nibic telluite glass sheets is shwn in Fig. 3. The tansmittance was deceased with an incease in the teatment tempeatue. When the tempeatue exceeded 70 C, the plasma esnant absptin f silve nancystals appeaed nea 500 nm. It seemed that when the tempeatue was lwe than 70 C, the cmbined pwe f the heat teatment and electic field culd nly induce a few Ag ins diffusing int the glass sheet. The cmbined pwe wuld begin t acceleate nucleatin and cystallizatin f nan-cystals simultaneusly when the tempeatue was geate than 70 C. Hweve, if the teatment tempeatue was t high, the glass will lse its tanspaence because f the lage size f the sepaated cystals, and the plasma esnant absptin was als deceased fm a dp f the quantum effects f the lage cystals. The telluite glass will be bken dwn when the electic filed intensity exceeds 700 mm/v at 350 C and highe. The influence f electic field intensity n the tansmittance f micscpy slides is als shwn in Fig. 4. Afte the slides wee implanted with Ag ins unde an electic field at 300 C, they wee e-annealed at 500 C V E 1 E The FESM pattens f silve nan-cystals in nibic telluite glasses. (a) The sectin f AgCl-cntaining telluite glass sheet afte being annealed at 360 C, (b) The sectin f telluite glass afte being diffused with Ag ins at 340 C unde an electic field, (c) The suface f telluite glass afte being diffused with Ag ins at 340 C unde an electic field. Fig..

4 Pepaatin f silve Nan-Cystal pattens in xide glasses unde electic field accmpanied by heat teatment 419 Fig. 5. A sketch f the heat teatment with a lcal aea applied electic field and the FESEM pattens f nibic telluite glass sheet. Fig. 3. Effect f teatment tempeatue n the tansmittance f telluite glass sheets unde an electic field accmpanied heat teatment f 350 V/mm. Fig. 6. Silve nan-cystal pattens in silicate glass slides. Fig. 4. Effect f electic field intensity n the tansmittance f silicate glass slides unde an electic field accmpanied heat teatment at 300 C t fm nan-cystal paticles. If the electic field intensity was t lw, it is difficult f Ag ins t diffuse int the dense glass netwk stuctue. When the electic field was pweful enugh, a lage amunt f Ag ins enteed the glass sheet alng the electic field lines, and then silve nan-cystals wee fmed by the e-annealing pcess, the plasma esnant absbing peak f silve nan-cystals can be seen appaently in Fig. 4. Tansfe pinting silve nan-cystal pattens int glass substates If nan-cystal paticles can be designed in desied pattens, they will have wide ptential applicatins in such aeas as manufactuing PIC, OEIC and sme the ptic electnic devices. The electic field has a high ientability, it can induce metal ins t diffuse int a glass substate alng the electic field lines and fm nan-cystal paticles in sme definite aeas. When the Ag in-cntaining glasses wee heated at a tempeatue little belw its nucleating and cystallizatin egin, the applied heat teatment cnditins wuld nt pvide enugh pwe t sepaate the cystals (as shwn in aea a f Fig. 5), while the lcal-aea applied auxiliay electic field will pvide the supplemental enegy t sepaate nan-cystals (as shwn in aea b f Fig. 5). When the electic field is used t implant metal ins int a glass substate, if its intensity is pweful enugh t let the ins diffuse int the glass, and the themal diffusin and cncentatin gadient diffusin can be estained as fa as pssible, the metal ins in the cated silve film patten will diffuse int the glass sheet mainly alng electic field lines, and then nan-cystal paticles can be sepaated in sme desied aeas unde an electic field accmpanied by heat teatment. Silve nan-cystal pattens ae shwn in Fig. 6. Afte cating with pattened silve paste n the suface f micscpe slides, the Ag ins wee implanted int the glass sheet unde a V/mm electic field at C, and then e-annealed at 500 C. A vaiety f silve nan-cystal pattens wee tansfe pinted int glass slides. The pattens aleady penetated int the glass slides t a depth f hundeds f micmetes, and thus the stability and wea esistance f these pattens wee much bette than thse made by chemical depsitin physical depsitin. Cnclusins Pepaatin f silve nan-cystal embedded glasses includes intducing Ag ins int the glass substates and sepaating nan-cystals fm the glass. Ag ins can be implanted int glass sheets fm a cated silve film unde a DC electic field accmpanied heat teatment. The electic field can als pvide supplemental enegy t cntl the

5 40 Jian Lin, Wen-Hai Huang, Shu-Hua Lei, Chang-Cheng Liu, Qi Bian, Li-Na Ma and Dng-Wei Li gwth f nan-cystals accuately duing heat teatment. When the heat teatment tempeatue is lw enugh t estain the cncentatin gadient diffusin, the electic field induced diffusin will play an imptant le. The highly diected electic field makes it pssible t well cntl the Ag -in-diffusin mainly alng the electic field line and then gw silve nan-cystals in desied lcal aeas, thus the silve nan-cystal pattens can be clealy tansfe pinted int telluite silicate glasses sheets. Acknwledgments Owing t the suppt fm Chinese Natinal Natue Science Fundatin (appved numbe ) and Shanghai Science and Technlgy Cmmittee (appved numbe 065nm00), this wk can be cmpleted. Refeences 1. S. Lysenk, J. Jimenez,. Zhang and H. Liu, J. Electn. Mate. 35[9] (007) B. hsh, P. Chakabty, S. Mhapata, P.A. Kuian, C. Vijayan, P.C. Deshmukh and P. Mazzldi, Mate. Lett 61[3-4] (007) Y. Hamanaka, N. Hayashi, A. Nakamua and S. Omi, J. Lumin [3-4] (000) L.E. Mi, A. Amluk and C. Bathu, J. Phys. Chem. Slids. 67[11] (006) B. Wu, S. Zhu, J. Ren, D. Chen, X. Jiang, C. Zhu and J. Qiu, Appl. Phys. B: Lases & Optics. 87[4] (007) A. Hhenau, H. Ditlbache, B. Lampecht, J.R. Kenn, A. Leitne and F.R. Aussenegg, Micelectn. Eng. 83[4-9] (006) A. Ritucci, A. Reale, P. Zuppella, L. Reale, P. Tuccei,. Tmassetti, P. Betttti and L. Pavesi, J. Appl. Phys. 10[3] (007) D.. Flagell and B. Amld, SPIE 637 (006) 6370D. 9. C. Pez, C. Heitz, E. Bathel, E. Sndegd and V. lett, J. Vacuum Sci. Tech. B 5[4] (007) L7-L J. Lin and W.H. Huang, Mate. Rev. 16[10] (00) F. Peng, K. Liang, A. Hu and H. Sha, Fuel. 83[14-15] (004) L. Zhu, D. Chen, W. Lu, Y. Wang, Y. Yu and F. Liu, Mate. Lett. 61[18] (007) J. Lin, W.H. Huang and L.Q. Lu, J. Ing. Mate. 0[3] (005) N.M. Feeia, S.K. Mendiatta and M.A. Valente, Mate. Sci. Fum (003) J. Sheng, J. Zheng, J. Zhang, C. Zhu and L. Jiang, Physica B: Cndensed Matte. 387[1-] (007) J. Lin, B. Li, C. Jing and W. Huang, J. Chinese Ceam. Sc. 34[4] (006)