简介:GaNmicrocrystallinegrainsweregrownbyhot-wallchemicalvapordepositiononSi(111)substrate.Thesegrainswithdiametersof2-4μmweredetectedbyscanningelectronmicroscopy.X-raydiffraction,Fouriertransformationinfraredtransmissionspectroscopyandphotoluminescencewereusedtoanalyzethestructure,compositionandtheopticalpropertiesofthesamples.TheresultsshowthatthemicrocrystallinegrainsarehexagonalwurtziteGaN,andthepropertyofthegrainswasgreatlyaffectedbythegrowthtime.
简介:Monolithicwhite-light-emittingdiodes(whiteLEDs)withoutphosphorsaredemonstratedusingInGaN/GaNmultiplequantumwells(MQWs)grownonGaNmicroringsformedbyselectiveareaepitaxyonSiO2maskpatterns.Themicroringstructureiscomposedof{1-101}semi-polarfacetsanda(0001)c-plane,attributedtofavorablesurfacepolarityandsurfaceenergy.ThewhitelightisrealizedbycombiningshortandlongwavelengthsofelectroluminescenceemissionsfromInGaN/GaNMQWsonthe{1-101}semi-polarfacetsandthe(0001)c-plane,respectively.ThechangeintheemissionwavelengthsfromeachmicrofacetisduetotheIncompositionvariationsoftheMQWs.Theseresultssuggestthatwhiteemissioncanpossiblybeobtainedwithoutusingphosphorsbycombiningemissionlightfrommicrostructures.
简介:Ⅲ族氮化物(又称GaN基)宽禁带半导体属于新兴的第三代半导体体系,在短波长光电子器件和功率电子器件领域具有重大应用价值。过去10多年,以蓝光和白光LED为核心的半导体照明技术和产业飞速发展,形成了对国家经济和人民生活产生显著影响的高技术产业。近年来GaN基功率电子器件受到了学术界和产业界的高度重视,形成了新的研发和产业化热点。首先介绍了半导体照明技术和产业的发展历程和现状,分析了当前GaN基LED芯片技术面临的关键科学和技术问题;然后重点介绍了GaN基微波功率器件和电力电子器件的发展历程和动态,包括微波功率器件已经取得的突破性进展和产业化现状,电力电子器件相对Si和SiC同类器件的优势和劣势,并对GaN基功率电子器件当前面临的关键科学和技术挑战进行了较详细的分析。
简介:在Al2O3(0001)衬底上用MOCDVD方法进行了GaN的外延生长,通过X射线衍射(同步辐射源)研究了GaN和Al2O3(0001)的匹配关系。结果表明,经充分氮化的衬底上,GaN以单一的匹配方式沿[0001]方向生长:在Al2O3(0001)衬底未经氮化或氮化不充分时,不同程度地出现了其它三种绕<11-20>晶带轴倾斜一定角度的匹配位向。指出了GaN/Al2O3(0001)的几种匹配方式的晶体学规律。GaN绕<11-20>晶带轴倾斜的匹配方式是其外延生长过程中降低和Al2O3(0001)的晶格失配、释放界面应变的重要机制之一。
简介:Inthispaper,theconductionband-edgenon-parabolicity(NP)andthecircularcross-sectionradiuseffectsonhydrogenicshallow-donorimpurityground-statebindingenergyinzinc-blende(ZB)InGaN/GaNcylindricalQWWsarereported.Thefinitepotentialbarrierbetween(In,Ga)NwellandGaNenvironmentisconsidered.Twomodelsoftheconductionband-edgenon-parabolicityaretakingintoaccount.Thevariationalapproachisusedwithintheframeworkofsinglebandeffective-massapproximationwithone-parametric1S-hydrogenictrialwave-function.ItisfoundthatNPeffectismorepronouncedinthewireofradiusequaltoeffectiveBohrradiusthaninlargeandnarrowwires.Moreover,thebindingenergypeakshiftstonarrowwireunderNPeffect.Agoodagreementisshowncomparedtothefindingsresults.
简介:摘要随着氮化镓(GaN)基发光二极管的效率、亮度、寿命等参数的进一步提升和成本的持续下降,GaN基LED正在逐渐取代传统光源在通用照明、液晶显示器背光源等领域的应用。高压LED是一种集成式芯片,将一块芯片分割成数个互联的发光单元,使得LED在高压低电流的状态下工作,与同样的传统大功率LED相比,高压LED的电流扩展性能和发光效率得到了提高。