Ngowama-2010, uGeim noNovoselov baphumelele iMbasa yeNobel kwifiziksi ngomsebenzi wabo kwigraphene. Eli bhaso lishiye umbono onzulu kubantu abaninzi. Kaloku, ayizizo zonke izixhobo zovavanyo zeNobel Prize eziqhelekileyo njengeteyiphu yokuncamathelisa, kwaye ayizizo zonke izinto zophando ezinomlingo kwaye kulula ukuziqonda njengegraphene "yekristale enamacala amabini". Umsebenzi ka-2004 unokunikezelwa ngo-2010, into engaqhelekanga kwirekhodi yeNobel Prize kwiminyaka yakutshanje.
I-Graphene luhlobo lwento equlathe umaleko omnye weeathom zekhabhoni ezicwangciswe ngokusondeleyo kwi-lattice ye-honeycomb enemilinganiselo emibini. Njengedayimani, i-graphite, i-fullerene, ii-carbon nanotubes kunye ne-carbon e-amorphous, yinto (into elula) eyenziwe zizinto zekhabhoni. Njengoko kubonisiwe kumfanekiso ongezantsi, ii-fullerene kunye nee-carbon nanotubes zinokubonwa njengezisongiwe ngandlela ithile kwi-layer enye ye-graphene, ehlanganiswe zii-layer ezininzi ze-graphene. Uphando lwethiyori malunga nokusetyenziswa kwe-graphene ukuchaza iipropati zezinto ezahlukeneyo zekhabhoni ezilula (i-graphite, ii-carbon nanotubes kunye ne-graphene) luhlale phantse iminyaka engama-60, kodwa ngokubanzi kukholelwa ukuba izinto ezinjalo ezinemilinganiselo emibini kunzima ukuziphila zodwa, zinamathele kuphela kumphezulu we-substrate onemilinganiselo emithathu okanye izinto ezingaphakathi ezifana ne-graphite. Kwakungekho de kwaba ngu-2004 apho u-Andre Geim kunye nomfundi wakhe uKonstantin Novoselov basusa umaleko omnye we-graphene kwi-graphite ngokusebenzisa iimvavanyo apho uphando lwe-graphene lufumene uphuhliso olutsha.
Zombini i-fullerene (ekhohlo) kunye ne-carbon nanotube (embindini) zinokuthathwa njengezisongwa lulwaleko olunye lwe-graphene ngandlela thile, ngelixa i-graphite (ekunene) ibekwe lulwaleko oluninzi lwe-graphene ngokudityaniswa kwamandla e-van der Waals.
Kule mihla, i-graphene inokufumaneka ngeendlela ezininzi, kwaye iindlela ezahlukeneyo zinezibonelelo kunye neengxaki zazo. UGeim noNovoselov bafumana i-graphene ngendlela elula. Besebenzisa iteyiphu ecacileyo efumaneka kwiivenkile ezinkulu, basusa i-graphene, iphepha le-graphite elinomaleko omnye kuphela wee-athomu zekhabhoni, kwisiqwenga se-graphite ye-pyrolytic ephezulu. Oku kulula, kodwa ukulawulwa kwayo akulunganga kangako, kwaye i-graphene enobukhulu obungaphantsi kwe-100 microns (isinye kwishumi se-millimeter) inokufunyanwa kuphela, enokusetyenziswa kwiimvavanyo, kodwa kunzima ukuyisebenzisa kwizicelo ezisebenzayo. Ukufakwa komphunga wekhemikhali kunokukhulisa iisampulu ze-graphene ezinobukhulu obungamashumi eesentimitha kumphezulu wesinyithi. Nangona indawo enoludwe oluhambelanayo yi-100 microns kuphela [3,4], ibifanelekile kwiimfuno zemveliso zezinye izicelo. Enye indlela eqhelekileyo kukutshisa i-silicon carbide (SIC) crystal ibe ngaphezulu kwe-1100 ℃ kwi-vacuum, ukuze ii-athomu ze-silicon ezikufutshane nomphezulu ziphele, kwaye ii-athomu zekhabhoni eziseleyo zihlengahlengiswe, ezinokufumana iisampulu ze-graphene ezineempawu ezilungileyo.
I-Graphene yinto entsha eneempawu ezizodwa: umbane wayo ungcono njengobhedu, kwaye ubushushu bayo bungcono kunayo nayiphi na into eyaziwayo. Ibonakala ngokucacileyo. Inxalenye encinci (2.3%) yokukhanya okubonakalayo okuthe nkqo okuya kutsalwa yi-graphene, kwaye uninzi lokukhanya luya kudlula. Ixinene kangangokuba neeathom ze-helium (iimolekyuli zegesi ezincinci) azinakudlula. Ezi mpawu zomlingo azizuzwa ngokuthe ngqo kwi-graphite, kodwa zivela kwi-quantum mechanics. Iimpawu zayo ezizodwa zombane kunye ne-optical zimisela ukuba inamathuba amaninzi okusetyenziswa.
Nangona i-graphene ivele ngaphantsi kweminyaka elishumi kuphela, ibonise usetyenziso oluninzi lobuchwephesha, olungaqhelekanga kakhulu kwicandelo lefiziksi kunye nesayensi yezinto eziphathekayo. Kuthatha iminyaka engaphezu kweshumi okanye amashumi eminyaka ukuba izinto eziqhelekileyo zisuke kwilebhu ziye kubomi bokwenyani. Iyintoni inzuzo ye-graphene? Makhe sijonge imizekelo emibini.
I-electrode ethambileyo nebonakalayo
Kwizixhobo ezininzi zombane, izixhobo zokuqhuba ezikhanyayo kufuneka zisetyenziswe njengee-electrode. Iiwotshi ze-elektroniki, ii-calculators, iithelevishini, izibonisi zekristale yolwelo, izikrini zokuchukumisa, iiphaneli zelanga kunye nezinye izixhobo ezininzi azinakushiya ubukho bee-electrode ezikhanyayo. I-electrode ekhanyayo yendabuko isebenzisa i-indium tin oxide (ITO). Ngenxa yexabiso eliphezulu kunye nokunikezelwa okuncinci kwe-indium, izinto ziyaqhekeka kwaye aziguquguquki, kwaye i-electrode kufuneka ifakwe kumaleko ophakathi we-vacuum, kwaye ixabiso liphezulu. Kangangexesha elide, izazinzulu bezizama ukufumana indawo yayo. Ukongeza kwiimfuno zokukhanya, ukuqhuba kakuhle kunye nokulungiselela okulula, ukuba ukuguquguquka kwezinto ngokwazo kulungile, kuya kufaneleka ekwenzeni "iphepha le-elektroniki" okanye ezinye izixhobo zokubonisa ezisongekayo. Ke ngoko, ukuguquguquka nako kukwayinto ebaluleke kakhulu. I-Graphene yinto enjalo, efanelekileyo kakhulu kwii-electrode ezikhanyayo.
Abaphandi abavela kwiYunivesithi yaseSamsung naseChengjunguan eMzantsi Korea bafumana i-graphene enobude obuyi-diagonal obuzii-intshi ezingama-30 nge-chemical vapor deposition baza bayidlulisela kwifilimu ye-polyethylene terephthalate (PET) enobukhulu obuyi-188 micron ukuze kuveliswe isikrini sokuchukumisa esisekelwe kwi-graphene [4]. Njengoko kubonisiwe kumfanekiso ongezantsi, i-graphene ekhuliswe kwi-copper foil iqala idityaniswe ne-thermal stripping tape (inxalenye eluhlaza okwesibhakabhaka ecacileyo), emva koko i-copper foil iyanyibilika ngendlela ye-chemical, kwaye ekugqibeleni i-graphene idluliselwa kwifilimu ye-PET ngokufudumeza.
Izixhobo ezintsha zokungenisa umbane ngefoto
I-Graphene ineempawu zokukhanya ezikhethekileyo kakhulu. Nangona kukho umaleko omnye kuphela wee-athomu, inokufunxa i-2.3% yokukhanya okukhutshiweyo kuluhlu lonke lwe-wavelength ukusuka ekukhanyeni okubonakalayo ukuya kwi-infrared. Eli nani alinanto yakwenza nezinye iiparameter zezinto ze-graphene kwaye limiselwa yi-quantum electrodynamics [6]. Ukukhanya okufunxiweyo kuya kukhokelela ekudalweni kwee-carriers (ii-electron kunye neengxunya). Ukuveliswa kunye nokuthuthwa kwee-carriers kwi-graphene kwahluke kakhulu kwezo zikwi-semiconductors zendabuko. Oku kwenza i-graphene ifaneleke kakhulu kwizixhobo zokungenisa i-photoelectric ezikhawulezayo. Kuqikelelwa ukuba izixhobo zokungenisa i-photoelectric ezinjalo zinokusebenza kwi-frequency ye-500ghz. Ukuba isetyenziselwa ukuhanjiswa kwesignali, inokudlulisa ii-zero ezingama-500 ezigidigidi okanye ezi-1 ngomzuzwana, kwaye igqibezele ukuhanjiswa kwezinto ezikwiidiski ezimbini ze-Blu ray ngomzuzwana omnye.
Iingcali ezivela kwi-IBM Thomas J. Watson Research Centre eMelika zisebenzise i-graphene ukwenza izixhobo zokungenisa i-photoelectric ezinokusebenza kwi-frequency ye-10GHz [8]. Okokuqala, ii-graphene flakes zalungiswa kwi-silicon substrate egqunywe yi-silica enobukhulu obuyi-300 nm "ngendlela yokukrazula i-tape", emva koko kwenziwa ii-electrodes zegolide ze-palladium okanye ze-titanium ezine-interval ye-1 micron kunye nobubanzi be-250 nm. Ngale ndlela, kufunyanwa isixhobo sokungenisa i-photoelectric esisekelwe kwi-graphene.
Umzobo weskemakhi wezixhobo ze-graphene photoelectric induction kunye neefoto ze-scanning electron microscope (SEM) zeesampuli zokwenyani. Umgca omfutshane omnyama kumfanekiso uhambelana nee-microns ezi-5, kwaye umgama phakathi kwemigca yesinyithi yi-micron enye.
Ngovavanyo, abaphandi bafumanise ukuba esi sixhobo sesinyithi se-graphene metal structure photoelectric induction sinokufikelela kwi-frequency yokusebenza ye-16ghz ubuninzi, kwaye sinokusebenza ngesantya esiphezulu kuluhlu lwamaza ukusuka kwi-300 nm (kufutshane ne-ultraviolet) ukuya kwi-6 microns (infrared), ngelixa ityhubhu yesiqhelo ye-photoelectric induction ayinakuphendula kukukhanya kwe-infrared ngobude obude. Ubuninzi bokusebenza kwezixhobo ze-graphene photoelectric induction kusenendawo entle yokuphucula. Ukusebenza kwayo okuphezulu kwenza ukuba ibe neendlela ezahlukeneyo zokusetyenziswa, kubandakanya unxibelelwano, ulawulo olukude kunye nokujonga okusingqongileyo.
Njengesixhobo esitsha esineempawu ezizodwa, uphando malunga nokusetyenziswa kwe-graphene luvela emva kwenye. Kunzima kuthi ukubala apha. Kwixesha elizayo, kunokubakho iityhubhu zempembelelo yentsimi ezenziwe nge-graphene, iiswitshi zeemolekyuli ezenziwe nge-graphene kunye nezixhobo zokufumanisa iimolekyuli ezenziwe nge-graphene kubomi bemihla ngemihla… I-Graphene ephuma kancinci kancinci kwilebhu iya kukhanya kubomi bemihla ngemihla.
Singalindela ukuba inani elikhulu leemveliso ze-elektroniki ezisebenzisa i-graphene liza kuvela kungekudala. Cinga ngendlela ebekuya kuba nomdla ngayo ukuba ii-smartphones kunye nee-netbooks zethu zinokusongwa, zibotshelelwe ezindlebeni zethu, zifakwe ezipokothweni zethu, okanye zisongelwe ezihlahleni zethu xa zingasetyenziswa!
Ixesha lokuthumela: Matshi-09-2022