Chinhu Chitsva Chinochinja - Silicon Nhema
Silicon nhema rudzi rutsva rwezvinhu zvesilicon zvine hunhu hwakanaka hwe optoelectronic. Chinyorwa chino chinopfupisa basa rekutsvagisa pamusoro pesilicon nhema naEric Mazur nevamwe vaongorori mumakore achangopfuura, vachitsanangura magadzirirwo uye maitiro ekugadzirwa kwesilicon nhema, pamwe chete nehunhu hwayo hwakadai sekunyudzwa, kupenya, kubuda kwemumunda, uye mhinduro ye spectral. Chinotaurawo nezvekushandiswa kwakakosha kwesilicon nhema mu infrared detectors, solar cells, uye flat-panels displays.
Crystalline silicon inoshandiswa zvakanyanya muindasitiri yesemiconductor nekuda kwezvakanakira zvayo zvakaita sekucheneswa nyore, nyore kushandisa zvinodhaka, uye kuramba kupisa kwakanyanya. Zvisinei, inewo matambudziko akawanda, akadai sekupenya kwakanyanya kwechiedza chinoonekwa uye che infrared pamusoro payo. Uyezve, nekuda kwegedhi rayo rakakura,silicon yekristarohaigone kupinza chiedza chine marefu echiedza anopfuura 1100 nm. Kana marefu echiedza chechiitiko akakura kupfuura 1100 nm, mwero wekupinza uye wekupindura kwezvioni zvesilicon unodzikira zvikuru. Zvimwe zvinhu zvakaita segermanium ne indium gallium arsenide zvinofanirwa kushandiswa kuona marefu aya. Zvisinei, mutengo wakakwira, hunhu husina kunaka hwethermodynamic uye mhando yekristaro, uye kusawirirana nemaitiro esilicon akakura aripo zvinodzikamisa kushandiswa kwazvo mumidziyo yakavakirwa pasilicon. Nokudaro, kuderedza kuratidzwa kwenzvimbo dzesilicon dzecrystalline uye kuwedzera huwandu hwemarefu ekuona mafoto detector akavakirwa pasilicon nesilicon hunoramba huri nyaya inonyanya kutsvakurudzwa.
Kuti kuderedze kuratidzwa kwe crystalline silicon surfaces, nzira dzakawanda dzekuedza dzakashandiswa, dzakadai se photolithography, reactive ion etching, uye electrochemical etching. Nzira idzi dzinogona, kusvika pamwero wakati, kuchinja chimiro che crystalline silicon pamusoro uye pedyo nepamusoro, nokudaro zvichideredzasilicon Kuratidzwa kwepadenga. Muchiedza chinoonekwa, kuderedza kuratidzwa kunogona kuwedzera kutorwa kwechiedza uye kuvandudza kushanda zvakanaka kwemuchina. Zvisinei, pahurefu hwemafungu hunopfuura 1100 nm, kana pasina huwandu hwesimba rekutorwa hunowanikwa mugomba rebhandi resilicon, kuratidzwa kwakaderera kunongotungamira mukuwedzera kwekutumira, nekuti gomba rebhandi resilicon rinopedzisira radzikamisa kutorwa kwaro kwechiedza cherefu-wavelength. Nokudaro, kuti uwedzere huwandu hwehurefu hwewavelength hwemidziyo inoenderana nesilicon uye silicon, zvakakosha kuwedzera kutorwa kwephoton mukati megomba rebhandi ukuwo uchideredza kuratidzwa kwesimbi yesilicon.
Mukupera kwema1990, Purofesa Eric Mazur nevamwe vekuHarvard University vakawana chinhu chitsva—silicon nhema—panguva yekutsvagisa kwavo pamusoro pekubatana kwemalaser e femtosecond nezvinhu, sezvakaratidzwa muMufananidzo 1. Pavaidzidza nezvehunhu hwe photoelectric hwesilicon nhema, Eric Mazur nevamwe vake vakashamisika kuona kuti chinhu ichi chesilicon chakagadzirwa ne microstructure chine hunhu hwakasiyana hwe photoelectric. Chinotora chiedza chinenge chese mu near-ultraviolet uye near-infrared range (0.25–2.5 μm), chichiratidza hunhu hwakanaka hwe luminescence hunoonekwa uye near-infrared uye hunhu hwakanaka hwekuburitsa simba mumunda. Kuwanikwa uku kwakakonzera kushamisika muindasitiri ye semiconductor, nemagazini makuru achikwikwidzana kuti ataure nezvacho. Muna 1999, magazini eScientific American neDiscover, muna 2000 chikamu chesainzi cheLos Angeles Times, uye muna 2001 magazini yeNew Scientist zvese zvakaburitsa zvinyorwa zvine chekuita nekuwanikwa kwesilicon nhema uye mashandisirwo ayo anogona kuitwa, zvichitenda kuti ine kukosha kwakakosha muminda yakaita seremote sensing, optical communications, uye microelectronics.
Parizvino, T. Samet wekuFrance, Anoife M. Moloney wekuIreland, Zhao Li wekuFudan University kuChina, naMen Haining vekuChinese Academy of Sciences vese vakaita tsvakiridzo yakakura pamusoro pesilicon nhema uye vakawana mhedzisiro yekutanga. SiOnyx, kambani iri kuMassachusetts, USA, yakatounganidza mari inosvika mamiriyoni gumi nerimwe emadhora ekushanda sepuratifomu yekuvandudza tekinoroji kune mamwe makambani, uye yakatanga kugadzirwa kwemawafers matema esilicon akavakirwa pamasensa, ichigadzirira kushandisa zvigadzirwa zvakapedzwa mumasisitimu emifananidzo yeinfrared yechizvarwa chinotevera. Stephen Saylor, CEO weSiOnyx, akataura kuti mabhenefiti etekinoroji yesilicon nhema inodhura zvishoma nezvishoma achakwezva kutarisa kwemakambani akatarisana nekutsvaga uye misika yemifananidzo yekurapa. Mune ramangwana, inogona kutopinda mumusika wemakamera edhijitari nemakamera ekhamera ane mabhiriyoni emadhora. SiOnyx parizvino iri kuyedzawo hunhu hwe photovoltaic hwesilicon nhema, uye zvingangoita kutisilicon nhemaichashandiswa mumasero ezuva mune ramangwana. 1. Maitiro Ekugadzira Black Silicon
1.1 Maitiro Ekugadzirira
Mawafer esilicon ane kristalo rimwe chete anocheneswa zvakatevedzana ne trichloroethylene, acetone, uye methanol, uye obva aiswa padanho rechinangwa rinofambiswa nemadimension matatu mukamuri re vacuum. Kumanikidzwa kwepasi kwekamuri re vacuum kuri pasi pe 1.3 × 10⁻² Pa. Gasi rinoshanda rinogona kuva SF₆, Cl₂, N₂, mhepo, H₂S, H₂, SiH₄, nezvimwewo, nekushanda kwe 6.7 × 10⁴ Pa. Neimwe nzira, nzvimbo ye vacuum inogona kushandiswa, kana kuti upfu hwe elemental hweS, Se, kana Te hunogona kuputirwa pamusoro pesilicon mu vacuum. Danho rechinangwa rinogonawo kunyudzwa mumvura. Mapundu eFemtosecond (800 nm, 100 fs, 500 μJ, 1 kHz) anogadzirwa neTi:sapphire laser regenerative amplifier anotariswa nelenzi uye anovhenekerwa zvakananga pamusoro pesilicon (simba rinobuda nelaser rinodzorwa neattenuator, ine hafu-wave plate uye polarizer). Nekufambisa danho rekunongedza kuti utarise pamusoro pesilicon ne laser spot, zvinhu zvesilicon nhema munzvimbo yakakura zvinogona kuwanikwa. Kuchinja daro riri pakati pelenzi nesilicon wafer kunogona kugadzirisa saizi yechiedza chinovhenekerwa pamusoro pesilicon, nokudaro kuchichinja laser fluence; kana saizi yenzvimbo yacho isingachinji, kuchinja kumhanya kwedanho rekunongedza kunogona kugadzirisa huwandu hwemapundu anovhenekerwa panzvimbo yeyuniti yesilicon surface. Gasi rinoshanda rinokanganisa zvakanyanya chimiro cheyuniti yesilicon surface. Kana gasi rinoshanda risingachinji, kuchinja laser fluence nehuwandu hwemapundu anogamuchirwa payuniti imwe neimwe kunogona kudzora kukwirira, chiyero cheaspect, uye nzvimbo ye microstructures.
1.2 Hunhu hweMicroscopic
Mushure mekupiswa nemwaranzi nelaser yefemtosecond, pamusoro pesilicon yakatsetseka pakutanga panoratidza zvivakwa zvidiki zveconical zvakarongwa nguva dzose. Makona ari panzvimbo imwechete nesilicon yakakomberedza isina kupiswa. Chimiro chechimiro checonical chakabatana negasi riri kushanda, sezvakaratidzwa muMufananidzo 2, apo zvivakwa zveconical zvinoratidzwa mu (a), (b), uye (c) zvinoumbwa mumhepo dzeSF₆, S, uye N₂, zvichiteerana. Zvisinei, kutungamira kwemakona hakunei negasi uye kunogara kuchinongedzera kwakanangana nelaser incidence, hakuchinjwi negravity, uye hakuneiwo nerudzi rwedoping, resistivity, uye crystal orientation yecrystalline silicon; macone bases haana kuenzana, ane short axis yawo yakafanana nelaser polarization direction. Makona akaumbwa mumhepo ndiwo akanyanya kuomarara, uye pamusoro pawo akafukidzwa ne dendritic nanostructures dzakatetepa dze10–100 nm.
Kana chiedza chelaser chakakwira uye huwandu hwemapulse hwakawedzera, ndipo panowedzera kureba uye kupamhama kwechimiro checonical. Mugasi reSF6, kureba h uye spacing d yezvivakwa zveconical zvine hukama husina kurongeka, hunogona kutaurwa se h∝dp, apo p=2.4±0.1; zvese kureba h uye spacing d zvinowedzera zvakanyanya nekuwedzera kwechiedza chelaser. Kana chiedza chikawedzera kubva pa5 kJ/m² kusvika pa10 kJ/m², spacing d inowedzera katatu, uye pamwe chete nehukama huripo pakati pe h na d, kureba h kunowedzera kagumi nembiri.
Mushure mekunyungudutswa kwemvura inopisa (1200 K, maawa matatu) mu vacuum, zvivakwa zve conical zvesilicon nhemaHazvina kuchinja zvakanyanya, asi 10–100 nm dendritic nanostructures pamusoro dzakadzikira zvikuru. Ion channeling spectroscopy yakaratidza kuti kusagadzikana pamusoro pekona kwakadzikira mushure mekunamirwa, asi zvivakwa zvakawanda zvisina kurongeka hazvina kuchinja pasi pemamiriro aya ekunamirwa.
1.3 Maitiro Ekugadzira
Parizvino, mashandiro ekugadzirwa kwesilicon nhema haana kujeka. Zvisinei, Eric Mazur nevamwe vake vakafungidzira, zvichibva pakuchinja kwechimiro chesilicon surface microstructure nemhepo inoshanda, kuti pasi pekukurudzirwa kwehigh-intensity femtosecond lasers, pane makemikari anoita pakati pegasi necrystalline silicon surface, zvichiita kuti silicon surface ichekwe nemamwe magasi, zvichiita kuti sharp cones dziite sharp cones. Eric Mazur nevamwe vake vakati mashandiro emuviri nemakemikari ekugadzirwa kwesilicon surface microstructure ane chekuita ne: kunyunguduka nekubvisa silicon substrate kunokonzerwa nehigh-fluence laser pulses; kubvisa silicon substrate ne reactive ions ne particles zvinogadzirwa ne strong laser field; uye recrystallization yechikamu chakabviswa chesubstrate silicon.
Zvimiro zveconical zviri pamusoro pesilicon zvinoumbwa zvega, uye array inenge yakajairwa inogona kugadzirwa pasina mask. MY Shen nevamwe vake vakabatanidza mesh yemhangura ye 2 μm thick transmission electron microscope copper pamusoro pesilicon se mask, uye vakazoisa silicon wafer muSF6 gas ne femtosecond laser. Vakawana array yakarongwa nguva dzose yezvimiro zveconical pamusoro pesilicon, zvinoenderana ne pattern ye mask (ona Mufananidzo 4). Saizi ye aperture ye mask inokanganisa zvakanyanya kurongeka kwezvimiro zveconical. Kupararira kwe incident laser ne mask apertures kunokonzera kusawirirana kwe laser energy pamusoro pesilicon, zvichikonzera kugoverwa kwe periodic temperature pamusoro pesilicon. Izvi zvinozoita kuti silicon surface structure array ive yakajairika.