LED na gargajiya ya kawo sauyi a fannin haske da nuni saboda ingancinsu, kwanciyar hankali da girman na'urar. LEDs galibi tarin fina-finan semiconductor ne masu sirara waɗanda ke da girman millimita a gefe, ƙanƙanta fiye da na'urorin gargajiya kamar kwararan fitila masu ƙonewa da bututun cathode. Duk da haka, aikace-aikacen optoelectronic masu tasowa, kamar kama-da-wane da gaskiyar da aka ƙara, suna buƙatar LEDs a girman microns ko ƙasa da haka. Fatan shine ƙananan - ko ƙananan LEDs (µleds) suna ci gaba da samun halaye masu kyau da yawa waɗanda LEDs na gargajiya suka riga suka mallaka, kamar fitar da hayaki mai ƙarfi, inganci mai yawa da haske, ƙarancin amfani da wutar lantarki, da fitar da haske mai cikakken launi, yayin da suke da ƙarancin kusan sau miliyan a yanki, wanda ke ba da damar ƙarin nunin faifai. Irin waɗannan guntun LED kuma za su iya buɗe hanya don ƙarin da'irori masu ƙarfi na photonic idan za a iya haɓaka su da guntu ɗaya akan Si kuma a haɗa su da na'urorin lantarki na ƙarfe oxide semiconductor (CMOS).
Duk da haka, zuwa yanzu, irin waɗannan µleds ɗin sun kasance ba a iya gani, musamman a cikin kewayon raƙuman haske na kore zuwa ja. Hanyar da aka saba amfani da ita ta hanyar jagorancin µ-led tsari ne na sama-ƙasa inda ake saka fina-finan InGaN quantum rijiyar (QW) a cikin na'urori masu ƙananan sikelin ta hanyar tsarin etching. Duk da cewa siraran tio2 µleds na InGaN QW masu sirara sun jawo hankali sosai saboda kyawawan halayen InGaN, kamar jigilar kaya mai inganci da kuma iya canza tsawon tsayi a duk faɗin kewayon da ake iya gani, har zuwa yanzu suna fama da matsaloli kamar lalacewar lalata gefen bango wanda ke ƙara ta'azzara yayin da girman na'urar ke raguwa. Bugu da ƙari, saboda wanzuwar filayen polarization, suna da rashin daidaiton tsayi/launi. Don wannan matsalar, an gabatar da mafita na InGaN da ramin kristal na photonic waɗanda ba na polar da semi-polar ba, amma ba su gamsar da su a halin yanzu ba.
A cikin wata sabuwar takarda da aka buga a cikin Light Science and Applications, masu bincike karkashin jagorancin Zetian Mi, farfesa a Jami'ar Michigan, Annabel, sun ƙirƙiro wani ƙaramin sikeli mai launin kore mai haske LED iii - nitride wanda ke shawo kan waɗannan cikas sau ɗaya kuma ga duka. An haɗa waɗannan µleds ta hanyar zaɓin yanki na plasma-assisted molecular beam epitaxy. Sabanin tsarin gargajiya na sama-ƙasa, µled a nan ya ƙunshi jerin nanowires, kowannensu diamita ne kawai 100 zuwa 200 nm, wanda aka raba da goma na nanometers. Wannan hanyar ƙasa-ƙasa tana hana lalacewar lalata bango a gefe.
Sashen da ke fitar da haske na na'urar, wanda kuma aka sani da yankin aiki, ya ƙunshi tsarin rijiyar quantum mai yawa (MQW) mai siffar core-shell wanda aka siffanta shi da siffar nanowire. Musamman ma, MQW ya ƙunshi rijiyar InGaN da shingen AlGaN. Saboda bambance-bambancen da ke tattare da ƙaurar atom ɗin da aka haɗa na abubuwan Rukunin III indium, gallium da aluminum a bangon gefe, mun gano cewa indium ya ɓace a bangon gefen nanowires, inda harsashin GaN/AlGaN ya naɗe tsakiyar MQW kamar burrito. Masu binciken sun gano cewa abun ciki na Al na wannan harsashin GaN/AlGaN ya ragu a hankali daga gefen allurar electron na nanowires zuwa gefen allurar rami. Saboda bambancin da ke cikin filayen rabuwar ciki na GaN da AlN, irin wannan juzu'in girma na abun ciki na Al a cikin layin AlGaN yana haifar da electrons kyauta, waɗanda suke da sauƙin kwarara zuwa cikin tsakiyar MQW kuma suna rage rashin daidaiton launi ta hanyar rage filin rabuwar.
A gaskiya ma, masu binciken sun gano cewa ga na'urori waɗanda ba su kai diamita ɗaya ba, tsawon ƙarfin lantarki, ko kuma fitar da hasken da ke haifar da wutar lantarki, ya kasance daidai gwargwado bisa ga girman canjin allurar da ake yi a yanzu. Bugu da ƙari, ƙungiyar Farfesa Mi ta riga ta ƙirƙiro wata hanya don haɓaka rufin GaN mai inganci akan silicon don haɓaka led nanowire akan silicon. Don haka, µled yana zaune akan wani abu mai Si wanda aka shirya don haɗawa da sauran na'urorin lantarki na CMOS.
Wannan µled yana da sauƙin amfani da shi. Dandalin na'urar zai ƙara ƙarfi yayin da tsawon fitar da iskar da ke cikin allon RGB da aka haɗa akan guntu ya faɗaɗa zuwa ja.
Lokacin Saƙo: Janairu-10-2023