演示文稿藍(lán)光寬帶隙激光器

演示文稿藍(lán)光寬帶隙激光器目前一頁\總數(shù)二十三頁\編于十六點(diǎn)（優(yōu)選）藍(lán)光寬帶隙激光器目前二頁\總數(shù)二十三頁\編于十六點(diǎn)Part1：GaNbluelaserdiodes目前三頁\總數(shù)二十三頁\編于十六點(diǎn)彩色激光顯示打印和掃描：快速、高分辨率存儲(chǔ)：CD(780nm)——AlGaAs基激光器

VCD(635nm或650nm)——AlGaInP激光器DVD(410nm)——InGaN激光器1-1Application目前四頁\總數(shù)二十三頁\編于十六點(diǎn)提高物鏡的數(shù)值孔徑NA值

容量與光源波長(zhǎng)的2次方成反比

光學(xué)元部件及光盤片材料的光學(xué)透過率等限制1-2OpticalStorage400-430nm1982年AlGaAs/GaAs(780nm)異質(zhì)結(jié)激光器作為光源的CD播放機(jī)1985年，KabayashiInGaAlP(670nm)紅光激光器的室溫連續(xù)激射1992年，HiroyamaInGaAlP(630nm)紅光半導(dǎo)體激光器1996年，日亞和中村GaN(400nm)藍(lán)紫光半導(dǎo)體激光器1999年，日亞實(shí)現(xiàn)商品化GaN(400nm)藍(lán)光半導(dǎo)體激光器壽命10000h目前五頁\總數(shù)二十三頁\編于十六點(diǎn)1-3DifficultiesandBreakthroughs難點(diǎn)缺乏晶格常數(shù)匹配、熱脹系數(shù)接近的熱穩(wěn)定的襯底材料p型GaN外延層難以獲得突破高質(zhì)量GaN外延層的生長(zhǎng)

1986年Amano利用低溫生長(zhǎng)的AlN或GaN過渡層或成核層,得到表面平坦如鏡低剩余載流子濃度、高電子遷移率和高熒光效率的高質(zhì)量GaN外延層,1991年首次獲得GaN外延層室溫光泵浦下的受激發(fā)射。低阻p-GaN的獲得

1989年Amano等人利用低能電子輻照實(shí)現(xiàn)了Mg摻雜低阻p型GaN。1991年Nakamura等人在700℃以上無氫的氮?dú)夥罩型嘶?也獲得了低阻p-GaN。高質(zhì)量InGaN外延層的生長(zhǎng)

有源層內(nèi)由In組分漲落引起的深局域化能態(tài)是發(fā)光二極管高效發(fā)光的關(guān)鍵,只有摻有In的GaN有源層才可能得到室溫帶間躍遷。目前六頁\總數(shù)二十三頁\編于十六點(diǎn)1-4Growth襯底的選擇生長(zhǎng)技術(shù)雙流生長(zhǎng)技術(shù)外延側(cè)向過生長(zhǎng)懸掛式外延目前七頁\總數(shù)二十三頁\編于十六點(diǎn)F-P腔結(jié)構(gòu)InGaN基激光器電注入的三級(jí)Bragg光柵紫光DFB激光器1-5Cavitystructure垂直腔面發(fā)射激光器極化聲子激光器目前八頁\總數(shù)二十三頁\編于十六點(diǎn)Part2：GaN-BasedVCSELandGaN-/ZnO-BasedPolaritonLasers目前九頁\總數(shù)二十三頁\編于十六點(diǎn)2-1Introductionmicrocavity(MC)-basedVCSELpolaritonlasersWithedge-emittingGaN-basedlasersincommercialsystems,attentionisshiftingtomoredemandingandrewardingemitters.High-speed,high-resolution

laser

printing

and

scanningNew

types

of

coherent

opticalbutnearlythresholdlesssourcesObservationofspontaneousem-issionbuildup

inpolaritonlasing

emissionisattributedtoaBose–

Einstein

condensateofcavitypol-aritons.目前十頁\總數(shù)二十三頁\編于十六點(diǎn)2-2GaN-BASEDVCSELThebeamofaVCSELischaracterizedbyalowerdivergenceanglecomparedwiththatoftheedge-emittinglasers,makingthemfavoredforuseinfiber-opticcommunications.Gainregionisveryshortinverticalcavitydevicesascomparedtheedge-emittervarieties,therequiredreflectivitiesofthetopandbottomDBRsmustbewellabove90%inordertoovercomeopticallossesforlasing.VCSELsemitperpendiculartotheactiveregionsurface,

allowingtheirfabrication

inadensetwo-dimensional

array.目前十一頁\總數(shù)二十三頁\編于十六點(diǎn)2-2-1OpticallyPumpedGaN-BasedVCSEL(1)AuthorYearTemperaturePumpingSomeyaetal.199877k381nmAsignificantnarrowingoftheemissionspectrafrom2.5nmto0.1nmabovethethresholdwasobserved,whichisdirectevidenceoflasingos--illationintheIn0.1Ga0.9NVCSEL.Science17September1999:Vol.285no.5435pp.1905-1906

AuthorYearTemperaturePumpingSomeyaetal.1999RT325nmLasingactionwasobservedatawavelengthof399nmunderopticalexcitationandconfirmedbyanarrowingofthelinewidthintheemissionspectrafrom0.8nmbelowthresholdtolessthan0.1nmabovethreshold.BottomDBR:43-pairGaN/Al0.34Ga0.66NCavity:26setsofIn0.01Ga0.99N/In0.1Ga0.9N

MQWsTop

DBR:15-pairZrO2/SiO2目前十二頁\總數(shù)二十三頁\編于十六點(diǎn)2-2-1OpticallyPumpedGaN-BasedVCSEL(2)AuthorYearTemperaturePumpingSongetal.1999RT400nmTop/BottomDBR:SiO2/HfO2Cavity:InGaN/GaN/AlGaNQWheterostructureDemonstratedacavityQfactorexceeding600ininitialexperiments,suggestingthattheapproachcanbeusefulforblueandnearultravioletRCLEDandVCSEL.AuthorYearTemperaturePumpingZhouetal.2000RT(300K)355nmBottomDBR:60-pairGaN/Al0.25Ga0.75NCavity:20setsofIn0.03Ga0.97N/InGaN

MQWsTop

DBR:15-pairSiO2/HfO2Demonstratedquasi-continuous-wave(CW)lasingoperationatroomtemperatureusingahybridcavitystructure目前十三頁\總數(shù)二十三頁\編于十六點(diǎn)2-2-1OpticallyPumpedGaN-BasedVCSEL(3)AuthorYearTemperaturePumpingTawaraetal.2003RT355nmExhibitedahighQfactorof460,aspontaneousemissionfactorofabout10-2,andlowthresholdof5.1mJ/cm-2.AuthorYearTemperaturePumpingFeltinetal.2005RT363.8nmDemonstratedthegreatpotentialofferedbythelattice-matchedAlInN/GaNmaterialsystemtorealisehighqualityMOVPE-grownadvancedoptoelectronicdevicessuchasVCSELsonGaNquasi-substrates.Top/BottomDBR:SiO2/ZrO2Cavity:threeperiods

ofIn0.02Ga0.98N(5nm)/In0.15Ga0.85N(2.5nm)

QWs

sandwichedbetweenAl0.07Ga0.93NlayersBottomDBR:28-pairAlInN/GaNCavity:2setsofIn0.15Ga0.85N/GaNMQWTop

DBR:23-pairAlInN/GaNDBRCrack-freehighreflectivityDBRs目前十四頁\總數(shù)二十三頁\編于十六點(diǎn)2-2-1OpticallyPumpedGaN-BasedVCSEL(4)AuthorYearTemperaturePumpingFeltinetal.2007RT297nmAlowaveragethresholdpumpenergydensityof200J/cm2wasachievedinacrack-freeplanarhybrid.Thisisalsoconduciveforelectricalinjection.AuthorYearTemperatureCastigliaetal.2007RT(300K)Demonstratedanefficientcurrentinjectionschemeinmicron-scaledareasforhighcurrentdensityoperationinverticallightemittingdevicesbyusingaLMAlInNoxidizedlayer.Acurrentdensityoftheorderof20kA/cm2hasbeenachieved,avaluewhichshouldfulfilltheinjectionrequirementsfornitride-basedVCSELs.BottomDBR:39.5-pairAl0.82In0.18N/GaNCavity:3setsofIn0.14Ga0.86N/GaN

QWsTop

DBR:13-pairSiO2/Si3N4目前十五頁\總數(shù)二十三頁\編于十六點(diǎn)2-2-2ElectricallyPumpedGaN-BasedVCSEL(1)電泵浦的GaN基VCSEL難點(diǎn)(1)難以獲得具有高質(zhì)量和高反射率的DBR

AlxGa1-xN和GaN之間折射率相差較大,因此二者搭配而成的DBR為GaN基VCSEL所普遍采用。但AlxGa1-xN和GaN之間晶格失配嚴(yán)重,它們的熱膨脹系數(shù)也相差較大。(2)缺少合適的p型接觸電極材料

p型GaN的功函數(shù)很高,很難找到理想的低阻歐姆接觸電極材料。VCSEL的電流注入既要求低接觸電阻又要求出光孔徑具有非常低的光學(xué)損耗,更增大了電極材料的難度。解決方案：在AlN/GaNDBR的制造過程中引入了超晶格結(jié)構(gòu),在出光孔徑上以氧化銦錫(ITO)作為接觸電極。目前十六頁\總數(shù)二十三頁\編于十六點(diǎn)2-2-2ElectricallyPumpedGaN-BasedVCSEL(2)AuthorYearTemperatureTurn-onVoltageThresholdCurrentWavelengthBetaDivergenceAnglePolarizationLuetal.200877K4.1V1.4mA462.8nm(0.15nm)7.5x10-211.7o80%BottomDBR:29-pairAlN/GaNDBR

threesets

of

a

5.5-pair

of

AlN/GaN

superlattice

wasinsertedeveryfourpairsofAlN/GaNCavity:n-GaN(790nm)tenperiodsofIn0.2Ga0.8N(2.5nm)/GaN(7.5nm)MQWsp-GaN(120nm)Top

DBR:8-pair

Ta2O5/SiO2DBR目前十七頁\總數(shù)二十三頁\編于十六點(diǎn)2-2-2ElectricallyPumpedGaN-BasedVCSEL(3)AuthorYearTemperatureTurn-onVoltageThresholdCurrentWavelengthHiguchietal.2008RT4.3V7.0mA414.4nm(0.03nm)BottomDBR:7-pairSiO2/Nb2O5Cavity:n-GaN(790nm)2-pairofInGaN(9nm)/GaN(13nm)MQWsp-GaN(120nm)Top

DBR:11.5-pairSiO2/Nb2O5Fabricatedavertical-current-injectionGaN-basedVCSELLasingactionatRTwasrealizedunderCWcurrentoperation.目前十八頁\總數(shù)二十三頁\編于十六點(diǎn)2-3WideBandgapSemiconductorPolaritonDevices在1996年Imamoglu及其合作者提出了極化聲子激光器的概念,他們是基于一種叫激子極化聲子的準(zhǔn)粒子提出此概念，這種準(zhǔn)粒子由光和物質(zhì)組成，產(chǎn)生于適當(dāng)設(shè)計(jì)的半導(dǎo)體晶體結(jié)構(gòu)中。PolaritonBose–EinsteincondensationLasingConditionPolaritonLasersExtremelylowthresholdlasers1998年，LeSiDang與其合作者在液氦溫度下觀察到極化激光。2007年，Southampton和Lausanne團(tuán)隊(duì)實(shí)現(xiàn)了具有光泵的第一個(gè)室溫極化聲子激光器。2012年，Iorsh基于氮化鎵（GaN）微腔的電泵浦極化聲子激光器優(yōu)化方案。目前十九頁\總數(shù)二十三頁\編于十六點(diǎn)2-3-1GaN-BasedMicrocavities-PolaritonLasersAuthorYearTemperatureThresholdMalpuechetal.2002RT1mWArealisticmodelforaroomtemperaturepolaritonlaserhasbeenproposedforaGaNMC.Itshowsanextremelylowthresholdpoweratroomtemperatureandahighquantumefficiency.BottomDBR:11-pairAl0.2Ga0.8N/Al0.9Ga0.1NCavity:9GaNQWsfourmonolayersTop

DBR:14-pairAl0.2Ga0.8N/Al0.9Ga0.1NAuthorYearTemperatureThresholdChristopoulosetal.2007RT1mWBottomDBR:34-pairAl0.85In0.15N/Al0.2Ga0:8NCavity:bulkGaNTop

DBR:10-pairSiO2/Si3N4Observearoom-temperaturelow-thresholdtransitiontoacoherentpolaritonstateinbulkGaNmicrocavitiesinthestrong-couplingregime.Aclearemissionthresholdof1mW,1orderofmagnitudesmallerthanthebestopticallypumped(In,Ga)Nquantum-wellVCSELs目前二十頁\總數(shù)二十三頁\編于十六點(diǎn)2-3-2ZnO-BasedMicrocavities(1)Anotherwide-bandgapsemiconductor,ZnO,isanattractivecandidateforUVoptoelectronicsdevices.ZnOhasanexcitonbindingenergy(60meV)thatismorethantwicethatofGaN(26meV).AuthorYearTemperatureThresholdShimadaetal.2008RT2mWBottomDBR:29-pairAl0.5Ga0.5N/GaNCavity:bulkZnOTop

DBR:8-pairSiO2/Si3N4RabisplittingAlargevacuumRabisplittingof

50