Ma LED achikhalidwe asintha kwambiri gawo la kuunikira ndi kuwonetsa chifukwa cha magwiridwe antchito awo apamwamba pankhani ya magwiridwe antchito, kukhazikika, ndi kukula kwa chipangizocho. Ma LED nthawi zambiri amakhala milu ya mafilimu opyapyala a semiconductor okhala ndi miyeso ya mbali ya mamilimita, ochepa kwambiri kuposa zida zachikhalidwe monga mababu a incandescent ndi machubu a cathode. Komabe, mapulogalamu atsopano a optoelectronic, monga virtual ndi augmented reality, amafunikira ma LED a kukula kwa ma micron kapena kuchepera. Chiyembekezo ndichakuti ma LED a micro - kapena submicron scale (µleds) akupitilizabe kukhala ndi makhalidwe ambiri apamwamba omwe ma LED achikhalidwe ali nawo kale, monga kutulutsa kokhazikika, kugwira ntchito bwino komanso kuwala, kugwiritsa ntchito mphamvu zochepa kwambiri, komanso kutulutsa utoto wonse, pomwe ali ochepa pafupifupi nthawi miliyoni m'dera, zomwe zimapangitsa kuti ziwonetsedwe zazing'ono zikhale zochepa. Ma chips a led oterewa amathanso kutsegula njira yama circuits amphamvu kwambiri ngati atha kulimidwa single-chip pa Si ndikugwirizanitsidwa ndi zida zamagetsi zachitsulo oxide semiconductor (CMOS).
Komabe, mpaka pano, ma µled oterewa akhalabe ovuta kuwapeza, makamaka pakati pa mafunde obiriwira mpaka ofiira. Njira yachikhalidwe ya led µ-led ndi njira yochokera pamwamba kupita pansi momwe mafilimu a InGaN quantum well (QW) amajambulidwa muzipangizo zazing'ono kudzera mu njira yojambula. Ngakhale ma tio2 µled a InGaN QW okhala ndi filimu yopyapyala akoka chidwi chachikulu chifukwa cha zinthu zambiri zabwino za InGaN, monga kunyamula bwino katundu komanso kusinthasintha kwa mafunde m'malo onse owoneka, mpaka pano akhala akuvutika ndi mavuto monga kuwonongeka kwa dzimbiri m'mbali mwa khoma komwe kumawonjezeka pamene kukula kwa chipangizo kukuchepa. Kuphatikiza apo, chifukwa cha kukhalapo kwa minda ya polarization, ali ndi kusakhazikika kwa mafunde/mtundu. Pa vutoli, mayankho a InGaN ndi ma crystal cavity omwe si a polar komanso a semi-polar aperekedwa, koma si okhutiritsa pakadali pano.
Mu pepala latsopano lofalitsidwa mu Light Science and Applications, ofufuza otsogozedwa ndi Zetian Mi, pulofesa ku University of Michigan, Annabel, apanga submicron green LED iii - nitride yomwe imagonjetsa zopinga izi kamodzi kokha. µleds izi zidapangidwa ndi selected regional plasma-assisted molecular beam epitaxy. Mosiyana kwambiri ndi njira yachikhalidwe yochokera pamwamba mpaka pansi, µled pano ili ndi ma nanowaya osiyanasiyana, iliyonse yokhala ndi mainchesi 100 mpaka 200 okha, yolekanitsidwa ndi ma nanometer makumi ambiri. Njira iyi yochokera pansi mpaka mmwamba kwenikweni imapewa kuwonongeka kwa dzimbiri pakhoma la mbali.
Gawo lotulutsa kuwala la chipangizochi, lomwe limadziwikanso kuti active region, limapangidwa ndi kapangidwe ka core-shell multiple quantum well (MQW) komwe kamadziwika ndi mawonekedwe a nanowire. Makamaka, MQW imakhala ndi InGaN well ndi AlGaN barrier. Chifukwa cha kusiyana kwa kusamuka kwa maatomu a Gulu III indium, gallium ndi aluminiyamu pamakoma am'mbali, tinapeza kuti indium inalibe pamakoma am'mbali a nanowires, komwe chipolopolo cha GaN/AlGaN chinakulunga MQW core ngati burrito. Ofufuzawo adapeza kuti kuchuluka kwa Al mu chipolopolo ichi cha GaN/AlGaN kunachepa pang'onopang'ono kuchokera kumbali ya injection ya ma elekitironi a nanowires kupita kumbali ya injection ya dzenje. Chifukwa cha kusiyana kwa minda yamkati ya polarization ya GaN ndi AlN, kuchuluka kwa Al mu Al layer ya AlGaN kumapangitsa ma free electron, omwe ndi osavuta kulowa mu MQW core ndikuchepetsa kusakhazikika kwa mtundu pochepetsa polarization field.
Ndipotu, ofufuza apeza kuti pa zipangizo zosakwana micron imodzi m'mimba mwake, kutalika kwa mafunde a electroluminescence, kapena kutulutsa kwa kuwala komwe kumayambitsidwa ndi magetsi, kumakhalabe kofanana ndi kusintha kwa jakisoni wa magetsi. Kuphatikiza apo, gulu la Pulofesa Mi lapanga kale njira yokulira zophimba za GaN zapamwamba kwambiri pa silicon kuti zikulitse ma nanowire LED pa silicon. Chifukwa chake, µled imakhala pa Si substrate yokonzeka kugwirizanitsidwa ndi zida zina zamagetsi za CMOS.
µled iyi ili ndi ntchito zambiri zomwe zingatheke. Pulatifomu ya chipangizochi idzakhala yolimba kwambiri pamene kutalika kwa mphamvu ya emission wa chiwonetsero cha RGB chophatikizidwa pa chip chikuwonjezeka kukhala chofiira.
Nthawi yotumizira: Januwale-10-2023