LED na al'ada ya canza fasalin haske da nuni saboda kyakkyawan aikinsu dangane da inganci, kwanciyar hankali da girman na'urar. LEDs yawanci tari ne na fina-finai na semiconductor na bakin ciki tare da girman milimita na gefe, sun fi ƙanƙanta fiye da na'urorin gargajiya kamar su kwararan fitila da bututun cathode. Koyaya, aikace-aikacen optoelectronic masu tasowa, kamar kama-da-wane da haɓaka gaskiyar, suna buƙatar LEDs a cikin girman microns ko ƙasa da haka. Fata shi ne cewa micro-ko submicron sikelin LED (µleds) ci gaba da samun da yawa daga cikin mafi ingancin halaye da na gargajiya jagororin da suka riga sun samu, kamar sosai barga watsi, high inganci da haske, matsananci-ƙananan wutar lantarki, da kuma cikakken launi watsi. yayin da yake kusan sau miliyan ƙarami a cikin yanki, yana ba da damar ƙarin nuni. Irin waɗannan kwakwalwan kwamfuta na iya ba da hanya don ƙarin ƙarfin da'irori na photonic idan za a iya girma guntu guda ɗaya akan Si kuma a haɗa su tare da na'urorin lantarki na karin ƙarfe oxide (CMOS).
Duk da haka, ya zuwa yanzu, irin waɗannan µleds sun kasance masu wuyar gaske, musamman a cikin kewayon tsayin iska mai kore zuwa ja. Hanyar jagorancin µ na gargajiya tsari ne na sama-sama wanda InGaN quantum well (QW) fina-finai ke zamewa cikin ƙananan na'urori ta hanyar etching tsari. Duk da yake fim ɗin InGaN QW tushen tio2 µleds na bakin ciki ya ja hankalin mutane da yawa saboda yawancin ingantattun kaddarorin InGaN, kamar ingantaccen jigilar jigilar kaya da tsayin tsayin tsayin daka a cikin kewayon bayyane, har zuwa yanzu suna fuskantar matsaloli kamar bangon gefe. Lalacewar lalata da ke daɗa muni yayin da girman na'urar ke raguwa. Bugu da ƙari, saboda kasancewar filayen polarization, suna da rashin kwanciyar hankali / launi. Don wannan matsalar, InGaN ba na iyakacin duniya da Semi-Polar da kuma hanyoyin magance kogon photonic crystal an gabatar da su, amma ba su da gamsarwa a halin yanzu.
A cikin sabon takarda da aka buga a Kimiyyar Haske da Aikace-aikace, masu bincike karkashin jagorancin Zetian Mi, farfesa a Jami'ar Michigan, Annabel, sun ɓullo da ma'auni na submicron green LED iii - nitride wanda ya shawo kan waɗannan matsalolin sau ɗaya. Waɗannan µleds an haɗa su ta hanyar zaɓin yanki na yanki wanda ke taimaka wa ƙwayar ƙwayar ƙwayar cuta ta ƙwayar cuta. Ya bambanta da tsarin gargajiya na sama zuwa ƙasa, µled a nan ya ƙunshi tsararrun nanowires, kowane kawai 100 zuwa 200 nm a diamita, ya rabu da dubun nanometers. Wannan hanyar zuwa sama da gaske tana guje wa lalata bangon gefe.
Bangaren da ke fitar da haske na na'urar, wanda kuma aka sani da yanki mai aiki, ya ƙunshi sifofi na core-shell mahara quantum rijiyar (MQW) da ke da sifofi na nanowire. Musamman, MQW ya ƙunshi rijiyar InGaN da shingen AlGaN. Saboda bambance-bambance a cikin ƙaurawar zarra na rukuni na uku indium, gallium da aluminum a bangon gefe, mun gano cewa indium ya ɓace a gefen bangon nanowires, inda harsashi GaN/AlGaN ya naɗe ainihin MQW kamar burrito. Masu binciken sun gano cewa abun cikin Al na wannan harsashi na GaN/AlGaN ya ragu a hankali daga bangaren allurar lantarki na nanowires zuwa bangaren allurar ramin. Sakamakon bambanci a cikin filayen polarization na ciki na GaN da AlN, irin wannan ƙarar ƙarar abun ciki na Al abun ciki a cikin AlGaN Layer yana haifar da electrons kyauta, waɗanda suke da sauƙin shiga cikin MQW core kuma suna rage rashin zaman lafiya ta launi ta hanyar rage filin polarization.
A gaskiya ma, masu binciken sun gano cewa ga na'urorin da ba su wuce micron daya ba a diamita, kololuwar tsayin wutar lantarki, ko fitar da hasken da ke fitowa a halin yanzu, yana ci gaba da kasancewa a kan tsari na girman canjin allura na yanzu. Bugu da ƙari, ƙungiyar Farfesa Mi a baya sun ƙirƙira wata hanya don haɓaka ingantattun suturar GaN akan siliki don haɓaka ledojin nanowire akan siliki. Don haka, µled yana zaune akan siginar Si wanda aka shirya don haɗawa da sauran na'urorin lantarki na CMOS.
Wannan µled cikin sauƙi yana da yuwuwar aikace-aikace. Dandalin na'urar za ta yi ƙarfi yayin da tsayin ƙuri'a na haɗe-haɗen nunin RGB akan guntu yana faɗaɗa ja.
Lokacin aikawa: Janairu-10-2023