Sabon Kayan Juyin Juya Hali - Baƙin Silikon
Baƙar silikon wani sabon nau'in kayan silicon ne mai kyawawan halayen optoelectronic. Wannan labarin ya taƙaita aikin bincike kan baƙin silikon da Eric Mazur da sauran masu bincike suka yi a cikin 'yan shekarun nan, yana ba da cikakken bayani game da tsarin shiri da samuwar baƙin silikon, da kuma halayensa kamar sha, hasken rana, fitar da iskar gas, da kuma amsawar spectral. Hakanan ya nuna mahimman amfani da baƙin silikon a cikin na'urorin gano infrared, ƙwayoyin hasken rana, da kuma nunin faifai.
Ana amfani da silicon na kristal sosai a masana'antar semiconductor saboda fa'idodinsa kamar sauƙin tsarkakewa, sauƙin amfani da doping, da juriya ga zafi mai yawa. Duk da haka, yana da matsaloli da yawa, kamar hasken da ake iya gani da kuma hasken infrared mai yawa a saman sa. Bugu da ƙari, saboda babban gibin da ke tsakaninsa da na'urar,silicon mai lu'ulu'uBa zai iya shan haske ba tare da tsawon tsayin da ya wuce 1100 nm. Idan tsawon hasken da ya faru ya fi 1100 nm, yawan sha da amsawar na'urorin gano silicon suna raguwa sosai. Dole ne a yi amfani da wasu kayayyaki kamar germanium da indium gallium arsenide don gano waɗannan tsawon tsayin da ya yi. Duk da haka, tsadar kayayyaki, rashin kyawun yanayin zafi da ingancin lu'ulu'u, da rashin jituwa da hanyoyin silicon da suka tsufa suna iyakance amfaninsu a cikin na'urori masu tushen silicon. Saboda haka, rage hasken saman lu'ulu'u da faɗaɗa kewayon tsawon tsayin da ya yi kama da na'urorin gano haske masu jituwa da silicon da silicon ya kasance babban batu na bincike.
Domin rage hasken saman silicon mai siffar crystalline, an yi amfani da hanyoyi da dabarun gwaji da yawa, kamar photolithography, reactive ion etching, da electrochemical etching. Waɗannan dabarun na iya, zuwa wani mataki, canza yanayin saman da kusa da saman silicon mai siffar crystalline, don haka ragesilicon Hasken saman. A cikin kewayon hasken da ake iya gani, rage haske na iya ƙara sha da inganta ingancin na'ura. Duk da haka, a tsawon raƙuman ruwa da suka wuce 1100 nm, idan ba a shigar da matakan kuzarin sha a cikin gibin silicon ba, raguwar haske yana haifar da ƙaruwar watsawa ne kawai, saboda gibin band na silicon a ƙarshe yana iyakance shan hasken dogon zango. Saboda haka, don faɗaɗa kewayon raƙuman ruwa masu mahimmanci na na'urori masu tushen silicon da masu jituwa da silicon, yana da mahimmanci a ƙara shaƙar photon a cikin gibin band yayin da a lokaci guda ake rage hasken silicon.
A ƙarshen shekarun 1990, Farfesa Eric Mazur da wasu a Jami'ar Harvard sun sami sabon abu - silicon baƙi - a lokacin bincikensu kan hulɗar lasers na femtosecond da abu, kamar yadda aka nuna a Hoto na 1. Yayin da suke nazarin halayen photoelectric na silicon baƙi, Eric Mazur da abokan aikinsa sun yi mamakin gano cewa wannan kayan silicon mai tsari yana da kaddarorin photoelectric na musamman. Yana ɗaukar kusan dukkan haske a cikin kewayon kusa-ultraviolet da kusa-infrared (0.25-2.5 μm), yana nuna kyawawan halaye na haske da na kusa-infrared da kyawawan halayen fitar da fili. Wannan gano ya haifar da jin daɗi a masana'antar semiconductor, tare da manyan mujallu suna fafutukar bayar da rahoto a kai. A cikin 1999, mujallun Scientific American and Discover, a cikin 2000 sashen kimiyya na Los Angeles Times, da kuma a cikin 2001 mujallar New Scientist duk sun buga labarai masu alaƙa da gano silicon baƙi da aikace-aikacensa, suna ganin yana da babban ƙima a fannoni kamar na'urar ji ta nesa, sadarwa ta gani, da microelectronics.
A halin yanzu, T. Samet daga Faransa, Anoife M. Moloney daga Ireland, Zhao Li daga Jami'ar Fudan da ke China, da Men Haining daga Kwalejin Kimiyya ta China duk sun gudanar da bincike mai zurfi kan silicon baƙi kuma sun cimma sakamako na farko. SiOnyx, wani kamfani a Massachusetts, Amurka, ya tara dala miliyan 11 a cikin jarin kamfani don zama dandamalin haɓaka fasaha ga wasu kamfanoni, kuma ya fara samar da wafers na silicon baƙi masu amfani da firikwensin, yana shirin amfani da samfuran da aka gama a cikin tsarin daukar hoto na infrared na gaba. Stephen Saylor, Shugaba na SiOnyx, ya bayyana cewa fa'idodin fasahar silicon baƙi masu rahusa da kuma yawan hankali za su jawo hankalin kamfanonin da suka mai da hankali kan bincike da kasuwannin daukar hoto na likita. A nan gaba, har ma za ta iya shiga kasuwar kyamarar dijital da kyamarar daukar hoto ta biliyan biliyan. SiOnyx kuma a halin yanzu tana gwaji da kaddarorin photovoltaic na silicon baƙi, kuma yana da yuwuwar cewa hakan zai iya faruwa.silicon baƙiza a yi amfani da shi a cikin ƙwayoyin hasken rana a nan gaba. 1. Tsarin Samar da Baƙin Silikon
1.1 Tsarin Shiri
Ana tsaftace wafers ɗin silicon guda ɗaya a jere da trichloroethylene, acetone, da methanol, sannan a sanya su a kan matakin manufa mai girma uku a cikin ɗakin injin. Matsin ƙasa na ɗakin injin yana ƙasa da 1.3 × 10⁻² Pa. Iskar gas ɗin da ke aiki na iya zama SF₆, Cl₂, N₂, iska, H₂S, H₂, SiH₄, da sauransu, tare da matsin lamba na aiki na 6.7 × 10⁴ Pa. A madadin haka, ana iya amfani da yanayin injin, ko kuma za a iya shafa foda na S, Se, ko Te a saman silicon a cikin injin injin. Hakanan ana iya nutsar da matakin da ake so a cikin ruwa. Ana mayar da hankali kan bugun femtosecond (800 nm, 100 fs, 500 μJ, 1 kHz) wanda aka samar ta hanyar amfani da na'urar ƙara ƙarfin sake farfaɗo da laser Ti:sapphire, sannan a haskaka shi a tsaye a saman silicon (ƙarfin fitarwa na laser yana sarrafawa ta hanyar mai rage zafi, wanda ya ƙunshi farantin rabin-wave da polarizer). Ta hanyar motsa matakin da aka nufa don duba saman silicon tare da wurin laser, ana iya samun kayan silicon baƙi mai girma. Canza nisan da ke tsakanin ruwan tabarau da wafer silicon zai iya daidaita girman wurin haske da aka haskaka akan saman silicon, ta haka ne zai canza tasirin laser; lokacin da girman wurin yake daidai, canza saurin motsi na matakin da aka nufa zai iya daidaita adadin bugun da aka haskaka akan yanki na yanki na saman silicon. Iskar gas mai aiki tana shafar siffar tsarin saman silicon sosai. Lokacin da iskar gas mai aiki take dawwama, canza tasirin laser da adadin bugun da aka karɓa a kowane yanki na sashi na iya sarrafa tsayi, rabon al'amari, da tazara na ƙananan sassan.
1.2 Halayen Allon Nuni
Bayan an yi amfani da hasken laser na femtosecond, saman silicon mai santsi na asali yana nuna jerin ƙananan tsarin conical da aka shirya su akai-akai. Saman conical suna kan layi ɗaya da saman silicon mara haske da ke kewaye. Siffar tsarin conical tana da alaƙa da iskar gas mai aiki, kamar yadda aka nuna a Hoto na 2, inda aka samar da tsarin conical da aka nuna a (a), (b), da (c) a cikin yanayin SF₆, S, da N₂, bi da bi. Duk da haka, alkiblar saman conical ba ta da alaƙa da iskar gas kuma koyaushe tana nuna alkiblar faruwar laser, ba ta da tasiri ga nauyi, kuma ba ta da alaƙa da nau'in doping, juriya, da yanayin lu'ulu'u na silicon crystalline; tushen conical ba su da daidaito, tare da gajeren axis ɗinsu daidai da alkiblar polarization na laser. Tsarin conical da aka samar a cikin iska sune mafi tsauri, kuma saman su an rufe su da mafi kyawun nanostructures na dendritic na 10-100 nm.
Yayin da ƙarfin tasirin laser ya yi yawa da kuma yawan bugun jini, haka nan tsayi da faɗin tsarin mazugi zai yi girma. A cikin iskar gas ta SF6, tsayin h da tazara d na tsarin mazugi suna da alaƙa mara layi, wanda za a iya bayyana shi kamar h∝dp, inda p=2.4±0.1; duka tsayin h da tazara d suna ƙaruwa sosai tare da ƙaruwar tasirin laser. Lokacin da tasirin ya ƙaru daga 5 kJ/m² zuwa 10 kJ/m², tazara d tana ƙaruwa da sau 3, kuma idan aka haɗa ta da alaƙar da ke tsakanin h da d, tsayin h yana ƙaruwa da sau 12.
Bayan an yi amfani da mannealing mai zafi sosai (1200 K, awanni 3) a cikin injin tsabtace iska, tsarin manne nasilicon baƙibai canza sosai ba, amma tsarin nanostructures na dendritic na 10-100 nm a saman ya ragu sosai. Gwajin ion channeling spectroscopy ya nuna cewa matsalar da ke kan saman manuni ta ragu bayan an cire shi, amma yawancin tsarin da ba su da tsari ba su canza ba a ƙarƙashin waɗannan yanayin annealing.
1.3 Tsarin Tsarawa
A halin yanzu, tsarin samuwar silicon baƙar fata bai bayyana ba. Duk da haka, Eric Mazur da abokan aikinsa sun yi hasashe, bisa ga canjin siffar tsarin saman silicon tare da yanayin aiki, cewa a ƙarƙashin ƙarfafawar lasers na femtosecond mai ƙarfi, akwai amsawar sinadarai tsakanin iskar gas da saman silicon mai lu'ulu'u, wanda ke ba da damar wasu iskar gas su lalata saman silicon, suna samar da mazurari masu kaifi. Eric Mazur da abokan aikinsa sun danganta hanyoyin zahiri da sinadarai na samuwar tsarin saman silicon zuwa: narkewa da kawar da sinadarin silicon da bugun laser mai ƙarfi ya haifar; goge sinadarin silicon ta hanyar ions da barbashi masu amsawa da aka samar ta hanyar ƙarfin filin laser; da sake kunna ɓangaren da aka cire na silicon mai lu'ulu'u.
Tsarin mazugi da ke kan saman silicon an samar da shi ba zato ba tsammani, kuma ana iya samar da tsari mai kama da na yau da kullun ba tare da abin rufe fuska ba. MY Shen da abokan aikinsa sun haɗa wani kauri na lantarki mai watsawa mai kauri μm 2 zuwa saman silicon a matsayin abin rufe fuska, sannan suka haskaka wafer ɗin silicon a cikin iskar SF6 tare da laser na femtosecond. Sun sami jerin tsare-tsaren mazugi da aka tsara akai-akai akan saman silicon, daidai da tsarin abin rufe fuska (duba Hoto na 4). Girman budewar abin rufe fuska yana shafar tsarin tsarin mazugi sosai. Rarrabawar laser da aka yi ta hanyar buɗewar abin rufe fuska yana haifar da rarraba makamashin laser mara daidaituwa akan saman silicon, wanda ke haifar da rarraba zafin jiki na lokaci-lokaci akan saman silicon. Wannan a ƙarshe yana tilasta jerin tsarin saman silicon ya zama na yau da kullun.