Mu ma diode otulutsa kuwala (ma LED) ochokera ku GaN, kupita patsogolo kosalekeza mu njira zokulirakulira za epitaxial ndi kapangidwe ka zida kwapangitsa kuti ntchito yamkati ya quantum efficiency (IQE) ikhale pafupi kwambiri ndi mphamvu yake yowunikira. Ngakhale kupita patsogolo kumeneku, magwiridwe antchito onse a ma LED akadali ocheperako chifukwa cha mphamvu yotulutsa kuwala (LEE). Popeza kuti safiro ikupitilirabe kukhala chinthu chofunikira kwambiri pa epitaxy ya GaN, mawonekedwe ake a pamwamba amakhala ndi gawo lofunika kwambiri pakulamulira kutayika kwa kuwala mkati mwa chipangizocho.

Nkhaniyi ikupereka kufananiza kwathunthu pakati pa miyala ya safiro yosalala ndi yopangidwa ndi mawonekedwemiyala ya safiro (PSS)Imafotokoza njira zowunikira ndi zowonera makristalo zomwe PSS imathandizira kuti kuwala kugwire bwino ntchito komanso imafotokoza chifukwa chake PSS yakhala muyezo weniweni popanga ma LED apamwamba kwambiri.

1. Kugwiritsa Ntchito Bwino Kuchotsa Magazi Ngati Botolo Lofunika Kwambiri

Kuchuluka kwa quantum efficiency (EQE) kwa LED kumatsimikiziridwa ndi zinthu ziwiri zazikulu:

$EQE=IQE\times LEE\backslash text\{EQE\}\; =\; \backslash text\{IQE\}\; \backslash times\; \backslash text\{LEE\}$

EQE=IQE×LEE

Ngakhale kuti IQE imawerengera momwe kuwala kumagwirira ntchito m'dera lomwe likugwira ntchito, LEE imafotokoza kachigawo ka ma photon opangidwa omwe amatuluka bwino mu chipangizocho.

Kwa ma LED ochokera ku GaN omwe amamera pazitsulo za safiro, LEE m'mapangidwe achikhalidwe nthawi zambiri imakhala yochepa pafupifupi 30–40%. Kulephera kumeneku kumachitika makamaka chifukwa cha:

• Kusagwirizana kwakukulu kwa refractive index pakati pa GaN (n ≈ 2.4), safiro (n ≈ 1.7), ndi mpweya (n ≈ 1.0)

• Kuwunikira kwamkati kwamphamvu (TIR) ​​pamawonekedwe ozungulira

• Kujambula kwa Photon mkati mwa zigawo za epitaxial ndi substrate

Motero, gawo lalikulu la ma photon opangidwa limadutsa mkati mwake ndipo pamapeto pake limatengedwa ndi zinthuzo kapena kusinthidwa kukhala kutentha m'malo mopereka kuwala kothandiza.

2. Zitsulo Zosanja za Sapphire: Zosavuta Kupanga ndi Zoletsa Zowoneka

2.1 Makhalidwe a Kapangidwe ka Nyumba

Ma substrates athyathyathya a safiro nthawi zambiri amagwiritsa ntchito mawonekedwe a c-plane (0001) okhala ndi malo osalala komanso ozungulira. Agwiritsidwa ntchito kwambiri chifukwa cha:

• Ubwino wapamwamba wa kristalo

• Kukhazikika kwabwino kwambiri kwa kutentha ndi mankhwala

• Njira zopangira zokhwima komanso zotsika mtengo

2.2 Khalidwe la Maso

Kuchokera ku kuwala, ma planar interfaces amatsogolera ku njira zofalikira za photon zomwe zimatsogolera kwambiri komanso zodziwikiratu. Pamene ma photon opangidwa mu gawo logwira ntchito la GaN akafika pa GaN-air kapena GaN-sapphire interface pa ngodya za ngozi zomwe zimapitirira ngodya yofunika kwambiri, kuwunikira konse kwamkati kumachitika.

Izi zimapangitsa kuti:

• Kutsekeka kwa photon mwamphamvu mkati mwa chipangizocho

• Kuwonjezeka kwa kuyamwa kwa ma electrode achitsulo ndi zilema zomwe zimachitika

• Kugawa kocheperako kwa kuwala kotuluka

Mwachidule, ma substrates a safiro osalala sathandiza kwenikweni polimbana ndi kutsekeka kwa maso.

3. Ma Substrates a Sapphire Opangidwa ndi Ma Pattern: Lingaliro ndi Kapangidwe ka Kapangidwe

Chomera cha safiro chokhala ndi mapatani (PSS) chimapangidwa poika zinthu zazing'ono kapena zazing'ono zomwe zimakhala ndi mawonekedwe a periodic kapena quasi-periodic pamwamba pa safiro pogwiritsa ntchito njira zojambulira ndi kupeta.

Ma geometri ofanana a PSS ndi awa:

• Kapangidwe ka mawonekedwe a conical

• Ma domes a Hemispherical

• Mawonekedwe a Piramidi

• Mawonekedwe a cylindrical kapena truncated-cone

Miyeso yanthawi zonse ya mawonekedwe imayambira pa sub-micrometer mpaka ma micrometer angapo, yokhala ndi kutalika koyang'aniridwa mosamala, mtunda, ndi kayendedwe ka ntchito.

4. Njira Zowonjezerera Kuwala mu PSS

4.1 Kuletsa Kuganizira Kwathunthu Kwamkati

Maonekedwe a PSS okhala ndi magawo atatu amasintha ma angles am'deralo a zochitika pa ma interfaces a zinthu. Ma photon omwe akanatha kuwona kuwunikira kwathunthu kwamkati pamalire athyathyathya amatumizidwa ku ma angles mkati mwa escape cone, zomwe zimawonjezera kwambiri mwayi wawo wotuluka mu chipangizocho.

4.2 Kufalikira kwa Mawonekedwe Owonjezera ndi Kusasinthika kwa Njira

Kapangidwe ka PSS kamayambitsa zochitika zingapo zobwerezabwereza ndi zowunikira, zomwe zimapangitsa kuti:

• Kusasinthika kwa njira zofalitsira photon

• Kuyanjana kwakukulu ndi mawonekedwe ochotsera kuwala

• Kuchepetsa nthawi yokhala ndi photon mkati mwa chipangizocho

Malinga ndi ziwerengero, zotsatirazi zimawonjezera mwayi woti photon ichotsedwe musanayambe kuyamwa.

4.3 Kulemba Magiredi Ogwira Ntchito a Refractive Index

Kuchokera pamalingaliro a optical modeling, PSS imagwira ntchito ngati refractive index transition layer yothandiza. M'malo mosintha mwadzidzidzi refractive index kuchokera ku GaN kupita ku mpweya, dera lopangidwa ndi mapatani limapereka kusintha pang'onopang'ono kwa refractive index, motero kuchepetsa kutayika kwa Fresnel reflection.

Njira imeneyi imafanana ndi zophimba zotsutsana ndi kuwunikira, ngakhale kuti imadalira ma optics a geometric osati kusokoneza kwa filimu yopyapyala.

4.4 Kuchepetsa Mwachindunji Kutayika kwa Mayamwidwe a Magazi

Mwa kufupikitsa kutalika kwa njira ya photon ndikuletsa kuwunikira kwamkati mobwerezabwereza, PSS imachepetsa mwayi woyamwa kwa kuwala ndi:

• Zolumikizira zitsulo

• Makhalidwe a zilema za kristalo

• Kulowetsedwa kwa Free-carrier mu GaN

Zotsatirazi zimathandiza kuti kutentha kugwire bwino ntchito komanso kuti kutentha kugwire bwino ntchito.

5. Ubwino Wowonjezera: Kukweza Ubwino wa Makristalo

Kupatula kuwonjezera kuwala, PSS imakonzanso khalidwe la zinthu za epitaxial kudzera mu njira zokulirakulira kwambiri za epitaxial (LEO):

• Kusokonekera kwa malo komwe kumayambira pa mawonekedwe a safiro-GaN kumasinthidwa kapena kuthetsedwa

• Kuchulukana kwa kusokonezeka kwa ulusi kumachepa kwambiri

• Ubwino wa kristalo umathandizira kudalirika kwa chipangizocho komanso nthawi yogwira ntchito

Phindu la mawonekedwe awiri ndi kapangidwe kameneka limasiyanitsa PSS ndi njira zongopangira mawonekedwe a pamwamba.

6. Kuyerekeza Kwazinthu: Sapphire Yathyathyathya vs. PSS

Kupambana kwenikweni kwa magwiridwe antchito kumadalira mawonekedwe a kapangidwe kake, kutalika kwa nthawi yotulutsa mpweya, kapangidwe ka chip, ndi njira yopangira.

7. Zoganizira Zokhudza Kusinthana ndi Uinjiniya

Ngakhale ubwino wake, PSS imabweretsa mavuto angapo othandiza:

• Njira zina zopangira lithography ndi etching zimawonjezera mtengo wopanga

• Kufanana kwa kapangidwe ndi kuya kwa etch kumafuna kuwongolera kolondola

• Mapangidwe osakonzedwa bwino angakhudze kwambiri kufanana kwa epitaxial

Chifukwa chake, kukonza PSS ndi ntchito yokhudzana ndi ntchito zosiyanasiyana zomwe zimaphatikizapo kuyerekezera kwa kuwala, uinjiniya wa kukula kwa epitaxial, ndi kapangidwe ka zida.

8. Mawonedwe a Makampani ndi Mawonedwe a Mtsogolo

Mu kupanga kwa LED kwamakono, PSS siikuonedwanso ngati njira yowonjezera yomwe ingatheke. Mu ntchito za LED zapakati ndi zapamwamba—kuphatikizapo kuunikira wamba, kuunikira kwamagalimoto, ndi kuunikira kumbuyo—yakhala ukadaulo woyambira.

Kafukufuku wamtsogolo ndi zochitika za chitukuko zikuphatikizapo:

• Mapangidwe apamwamba a PSS opangidwira ntchito za Mini-LED ndi Micro-LED

• Njira zosakanikirana zophatikiza PSS ndi makristalo a photonic kapena mawonekedwe a nanoscale surface

• Kupitiliza kuyesetsa kuchepetsa ndalama ndi ukadaulo wokonzera mapangidwe

Mapeto

Ma substrates okhala ndi mapangidwe a safiro amayimira kusintha kwakukulu kuchokera ku zothandizira zamagetsi zopanda ntchito kupita ku zida zogwirira ntchito za kuwala ndi kapangidwe kake muzipangizo za LED. Mwa kuthana ndi kutayika kwa kuwala komwe kumachokera muzu wawo—monga kutsekedwa kwa kuwala ndi kuwunikira kwa mawonekedwe—PSS imalola kugwira ntchito bwino kwambiri, kudalirika bwino, komanso magwiridwe antchito okhazikika a chipangizocho.

Mosiyana ndi zimenezi, ngakhale kuti zinthu zopangidwa ndi safiro zimakhala zokongola chifukwa cha kupangika kwawo komanso mtengo wotsika, zofooka zawo zowunikira zimalepheretsa kuyenerera kwa ma LED a m'badwo wotsatira omwe amagwira ntchito bwino kwambiri. Pamene ukadaulo wa LED ukupitirirabe kusintha, PSS ndi chitsanzo chomveka bwino cha momwe uinjiniya wa zinthu ungasinthire mwachindunji kuti pakhale phindu pa magwiridwe antchito a dongosolo.