Ib qho khoom siv tshiab uas hloov pauv tas li - Black Silicon
Silicon dub yog ib hom khoom siv silicon tshiab uas muaj cov khoom siv optoelectronic zoo heev. Tsab xov xwm no piav qhia txog kev tshawb fawb txog silicon dub los ntawm Eric Mazur thiab lwm tus kws tshawb fawb hauv xyoo tas los no, piav qhia txog kev npaj thiab tsim cov txheej txheem ntawm silicon dub, nrog rau nws cov khoom xws li kev nqus, kev ci ntsa iab, kev tso tawm teb, thiab kev teb spectral. Nws kuj taw qhia txog cov kev siv tseem ceeb ntawm silicon dub hauv cov khoom siv infrared, cov roj teeb hnub ci, thiab cov zaub tiaj tus.
Crystalline silicon yog siv dav hauv kev lag luam semiconductor vim nws qhov zoo xws li yooj yim ntawm kev ntxuav, yooj yim ntawm doping, thiab tiv taus kub siab. Txawm li cas los xij, nws kuj muaj ntau qhov tsis zoo, xws li kev cuam tshuam siab ntawm lub teeb pom kev thiab infrared ntawm nws qhov chaw. Ntxiv mus, vim nws qhov sib txawv loj,cov pob zeb crystalline silicontsis tuaj yeem nqus lub teeb nrog cov wavelengths loj dua 1100 nm. Thaum lub wavelength ntawm lub teeb tshwm sim loj dua 1100 nm, qhov kev nqus thiab teb ntawm cov khoom siv silicon detectors raug txo qis heev. Lwm cov ntaub ntawv xws li germanium thiab indium gallium arsenide yuav tsum tau siv los ntes cov wavelengths no. Txawm li cas los xij, tus nqi siab, cov khoom thermodynamic tsis zoo thiab cov khoom siv crystal zoo, thiab tsis sib xws nrog cov txheej txheem silicon uas twb muaj lawm txwv lawv daim ntawv thov hauv cov khoom siv silicon. Yog li ntawd, txo qhov kev cuam tshuam ntawm cov crystalline silicon nto thiab txuas ntxiv qhov ntau ntawm qhov kev ntes wavelength ntawm silicon-based thiab silicon-compatible photodetectors tseem yog ib qho kev tshawb fawb kub.
Yuav kom txo qhov kev cuam tshuam ntawm cov nplaim crystalline silicon, ntau txoj kev sim thiab cov txheej txheem tau siv, xws li photolithography, reactive ion etching, thiab electrochemical etching. Cov txheej txheem no tuaj yeem, qee qhov, hloov pauv qhov chaw thiab ze ntawm qhov chaw ntawm crystalline silicon, yog li txosilicon Kev cuam tshuam ntawm qhov chaw. Hauv qhov pom kev, kev txo qhov cuam tshuam tuaj yeem ua rau kev nqus tau ntau dua thiab txhim kho kev ua haujlwm ntawm lub cuab yeej. Txawm li cas los xij, ntawm qhov ntev tshaj 1100 nm, yog tias tsis muaj qib zog nqus tau nkag mus rau hauv qhov sib txawv ntawm silicon, kev cuam tshuam tsawg dua tsuas yog ua rau muaj kev sib kis ntau dua, vim tias qhov sib txawv ntawm silicon thaum kawg txwv nws qhov kev nqus ntawm lub teeb ntev ntev. Yog li ntawd, txhawm rau txuas ntxiv qhov ntau ntawm qhov ntev ntawm cov khoom siv silicon thiab silicon-compatible, nws yog qhov tsim nyog los nce kev nqus photon hauv qhov sib txawv ntawm qhov sib txawv thaum tib lub sijhawm txo qhov kev cuam tshuam ntawm silicon.
Thaum xyoo 1990s lig, Xibfwb Eric Mazur thiab lwm tus ntawm Harvard University tau txais cov khoom tshiab - silicon dub - thaum lawv tshawb fawb txog kev sib cuam tshuam ntawm femtosecond lasers nrog cov khoom, raws li pom hauv Daim Duab 1. Thaum kawm txog cov khoom siv photoelectric ntawm silicon dub, Eric Mazur thiab nws cov npoj yaig xav tsis thoob thaum pom tias cov khoom siv silicon microstructured no muaj cov khoom siv photoelectric tshwj xeeb. Nws nqus yuav luag txhua lub teeb hauv qhov ze-ultraviolet thiab ze-infrared (0.25–2.5 μm), qhia txog cov yam ntxwv pom zoo heev thiab ze-infrared luminescence thiab cov khoom siv emission zoo. Qhov kev tshawb pom no ua rau muaj kev xav hauv kev lag luam semiconductor, nrog rau cov ntawv xov xwm loj sib tw los tshaj tawm txog nws. Xyoo 1999, Scientific American thiab Discover magazines, xyoo 2000 Los Angeles Times science section, thiab xyoo 2001 New Scientist magazine txhua tus tau luam tawm cov ntawv xov xwm tshwj xeeb tham txog kev tshawb pom ntawm silicon dub thiab nws cov ntawv thov muaj peev xwm, ntseeg tias nws muaj txiaj ntsig zoo hauv cov teb xws li kev tshawb nrhiav chaw deb, kev sib txuas lus optical, thiab microelectronics.
Tam sim no, T. Samet los ntawm Fabkis teb, Anoife M. Moloney los ntawm Ireland, Zhao Li los ntawm Fudan University hauv Suav teb, thiab Men Haining los ntawm Chinese Academy of Sciences tau ua kev tshawb fawb ntau yam txog cov silicon dub thiab tau txais cov txiaj ntsig thawj zaug. SiOnyx, ib lub tuam txhab hauv Massachusetts, Tebchaws Meskas, tau tsa $ 11 lab nyiaj los ua lub platform tsim kho thev naus laus zis rau lwm lub tuam txhab, thiab tau pib tsim cov khoom lag luam ntawm cov wafers silicon dub uas siv sensor, npaj siv cov khoom tiav hauv cov tshuab duab infrared tiam tom ntej. Stephen Saylor, CEO ntawm SiOnyx, tau hais tias cov txiaj ntsig pheej yig thiab muaj kev nkag siab zoo ntawm cov thev naus laus zis silicon dub yuav nyiam cov tuam txhab uas tsom mus rau kev tshawb fawb thiab kev lag luam duab kho mob. Yav tom ntej, nws yuav nkag mus rau hauv kev lag luam koob yees duab digital thiab camcorder ntau txhiab daus las. SiOnyx kuj tseem tab tom sim nrog cov khoom photovoltaic ntawm silicon dub, thiab nws muaj feem ntau tiassilicon dubyuav siv rau hauv cov hlwb hnub ci yav tom ntej. 1. Cov txheej txheem tsim ntawm Black Silicon
1.1 Txheej Txheem Npaj
Cov silicon wafers ib leeg-siv lead ua ke raug ntxuav ua ntu zus nrog trichloroethylene, acetone, thiab methanol, thiab tom qab ntawd muab tso rau ntawm theem peb-seem uas txav tau hauv lub tshuab nqus tsev. Lub hauv paus siab ntawm lub tshuab nqus tsev yog tsawg dua 1.3 × 10⁻² Pa. Cov roj ua haujlwm tuaj yeem yog SF₆, Cl₂, N₂, cua, H₂S, H₂, SiH₄, thiab lwm yam, nrog lub siab ua haujlwm ntawm 6.7 × 10⁴ Pa. Xwb, ib puag ncig nqus tsev tuaj yeem siv, lossis cov hmoov av ntawm S, Se, lossis Te tuaj yeem coated rau ntawm qhov chaw silicon hauv lub tshuab nqus tsev. Lub hom phiaj theem kuj tuaj yeem raug raus rau hauv dej. Cov pulses Femtosecond (800 nm, 100 fs, 500 μJ, 1 kHz) uas tsim los ntawm Ti:sapphire laser regenerative amplifier raug tsom los ntawm lub lens thiab irradiated perpendicularly rau ntawm qhov chaw silicon (lub zog tso zis laser yog tswj los ntawm lub attenuator, uas muaj ib nrab-yoj phaj thiab lub polarizer). Los ntawm kev txav lub hom phiaj theem mus rau scan qhov chaw silicon nrog lub laser qhov chaw, cov khoom siv silicon dub loj-cheeb tsam tuaj yeem tau txais. Kev hloov qhov deb ntawm lub lens thiab lub silicon wafer tuaj yeem kho qhov loj ntawm lub teeb qhov chaw irradiated rau ntawm qhov chaw silicon, yog li hloov lub laser fluence; thaum qhov loj ntawm qhov chaw yog tas li, kev hloov qhov ceev ntawm lub hom phiaj theem tuaj yeem kho tus lej ntawm cov pulses irradiated rau ntawm ib cheeb tsam ntawm qhov chaw silicon. Cov roj ua haujlwm cuam tshuam rau cov duab ntawm cov qauv ntawm qhov chaw silicon. Thaum cov roj ua haujlwm yog tas li, kev hloov lub laser fluence thiab tus lej ntawm cov pulses tau txais ib cheeb tsam tuaj yeem tswj qhov siab, qhov sib piv, thiab qhov sib nrug ntawm cov qauv.
1.2 Cov Yam Ntxim Saib ntawm Lub Tshuab Microscopic
Tom qab femtosecond laser irradiation, qhov chaw silicon crystalline du uas yog thawj zaug pom ntau yam qauv me me uas tau teeb tsa zoo li qub. Cov saum toj ntawm lub khob hliav qab nyob rau tib lub dav hlau li qhov chaw silicon uas tsis tau irradiated. Cov duab ntawm cov qauv conical muaj feem cuam tshuam nrog cov roj ua haujlwm, raws li pom hauv Daim Duab 2, qhov twg cov qauv conical pom hauv (a), (b), thiab (c) tau tsim nyob rau hauv SF₆, S, thiab N₂ atmospheres, raws li. Txawm li cas los xij, qhov kev taw qhia ntawm cov saum toj ntawm lub khob hliav qab yog ywj pheej ntawm cov roj thiab ib txwm taw tes rau hauv qhov kev taw qhia ntawm laser, tsis cuam tshuam los ntawm lub ntiajteb txawj nqus, thiab kuj ywj pheej ntawm hom doping, resistivity, thiab crystal orientation ntawm crystalline silicon; cov hauv paus cone yog asymmetrical, nrog lawv cov axis luv luv sib luag rau qhov kev taw qhia polarization laser. Cov qauv conical tsim nyob rau hauv huab cua yog qhov ntxhib tshaj plaws, thiab lawv cov nplaim yog them nrog txawm tias finer dendritic nanostructures ntawm 10–100 nm.
Qhov siab dua ntawm laser fluence thiab qhov ntau dua ntawm cov pulses, qhov siab dua thiab dav dua cov qauv conical ua. Hauv SF6 roj, qhov siab h thiab qhov sib nrug d ntawm cov qauv conical muaj kev sib raug zoo nonlinear, uas tuaj yeem kwv yees li h∝dp, qhov twg p = 2.4 ± 0.1; ob qho tib si qhov siab h thiab qhov sib nrug d nce ntxiv nrog rau kev nce laser fluence. Thaum qhov fluence nce ntawm 5 kJ / m² txog 10 kJ / m², qhov sib nrug d nce 3 zaug, thiab ua ke nrog kev sib raug zoo ntawm h thiab d, qhov siab h nce 12 zaug.
Tom qab kub siab annealing (1200 K, 3 teev) nyob rau hauv lub tshuab nqus tsev, cov qauv conical ntawmsilicon dubtsis hloov pauv ntau, tab sis cov 10–100 nm dendritic nanostructures ntawm qhov chaw tau txo qis heev. Ion channeling spectroscopy qhia tau hais tias qhov kev tsis sib haum xeeb ntawm qhov chaw conical tau txo qis tom qab annealing, tab sis feem ntau ntawm cov qauv tsis sib haum xeeb tsis hloov pauv nyob rau hauv cov xwm txheej annealing no.
1.3 Txoj Kev Tsim Kho
Tam sim no, txoj kev tsim cov silicon dub tsis meej. Txawm li cas los xij, Eric Mazur et al. xav tias, raws li kev hloov pauv ntawm cov duab ntawm silicon nto microstructure nrog rau huab cua ua haujlwm, tias nyob rau hauv kev txhawb nqa ntawm cov lasers femtosecond siab, muaj kev tshuaj lom neeg ntawm cov roj thiab qhov chaw crystalline silicon, tso cai rau qhov chaw silicon kom raug etched los ntawm qee cov roj, tsim cov cones ntse. Eric Mazur et al. tau hais tias cov txheej txheem lub cev thiab tshuaj lom neeg ntawm silicon nto microstructure tsim rau: yaj thiab ablation ntawm silicon substrate los ntawm high-fluence laser pulses; etching ntawm silicon substrate los ntawm reactive ions thiab cov khoom me me tsim los ntawm lub zog laser teb; thiab recrystallization ntawm ablated ib feem ntawm substrate silicon.
Cov qauv conical ntawm qhov chaw silicon yog tsim los ntawm nws tus kheej, thiab ib qho quasi-regular array tuaj yeem tsim tau yam tsis muaj lub ntsej muag. MY Shen et al. tau txuas ib lub 2 μm tuab transmission electron microscope tooj liab mesh rau ntawm qhov chaw silicon ua lub ntsej muag, thiab tom qab ntawd irradiated lub silicon wafer hauv SF6 roj nrog lub femtosecond laser. Lawv tau txais ib qho array tsis tu ncua ntawm cov qauv conical ntawm qhov chaw silicon, sib xws nrog cov qauv lub ntsej muag (saib Daim Duab 4). Qhov loj me ntawm lub ntsej muag cuam tshuam rau qhov kev npaj ntawm cov qauv conical. Qhov diffraction ntawm qhov teeb meem laser los ntawm lub ntsej muag apertures ua rau muaj kev faib tawm tsis sib xws ntawm lub zog laser ntawm qhov chaw silicon, ua rau muaj kev faib tawm kub tsis tu ncua ntawm qhov chaw silicon. Qhov no thaum kawg yuam kom cov qauv silicon nto array ua ib txwm.