氮化镓基绿光LED中V坑对空穴电流分布的影响
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摘要
采用实验与理论模拟相结合的方法,研究了氮化镓基绿光发光二极管(LED)中V坑对空穴电流分布的影响。首先,实验获得了V坑面积占比不同的3种样品;然后,建立数值模型,使得理论计算的外量子效率(EQE)及电压与实验测试的变化趋势相匹配,从而确立了所用数值模型的可信性。计算结果显示:V坑改变了空穴电流的分布,空穴电流密度在V坑处显著增加,在平台处明显减小。进一步的分析表明:V坑面积占比在0~10%范围内,V坑空穴电流占比与V坑面积占比之间呈近线性增长(斜率为2.06),但V坑空穴注入在整个空穴注入的过程中仍未占主导。
The effect of V-shaped pit hole current distributionin Ga N based green LED was experimentally and theoretically investigated. First,three LED samples were prepared by experiment,which V-shaped pit area ratio was different. Then,a numerical model was established to match the external quantum efficiency( EQE) and the voltage of the theoretical calculation with the trend of the experimental test,thus the credibility of the numerical model was established. Calculation results show that the V-shaped pit changes the distribution of hole current,the hole current density increases significantly in the V-shaped pit,and reduces significantly at the platform. Further,the analysis shows that the hole current ratio in the V-shaped pit shows a near linear increase with the V-shaped pit area ratio( slope is 2. 06) when the V-shaped pit area ratio is in the range of 0-10%,while the V-shaped pit hole injection has not yet dominated the whole hole injection process.
The effect of V-shaped pit hole current distributionin Ga N based green LED was experimentally and theoretically investigated. First,three LED samples were prepared by experiment,which V-shaped pit area ratio was different. Then,a numerical model was established to match the external quantum efficiency( EQE) and the voltage of the theoretical calculation with the trend of the experimental test,thus the credibility of the numerical model was established. Calculation results show that the V-shaped pit changes the distribution of hole current,the hole current density increases significantly in the V-shaped pit,and reduces significantly at the platform. Further,the analysis shows that the hole current ratio in the V-shaped pit shows a near linear increase with the V-shaped pit area ratio( slope is 2. 06) when the V-shaped pit area ratio is in the range of 0-10%,while the V-shaped pit hole injection has not yet dominated the whole hole injection process.
引文
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[31]ZHANG Y P,ZHANG Z H,LIU W,et al..Nonradiative recombination--critical in choosing quantum well number for In Ga N/Ga N light-emitting diodes[J].Opt.Express,2015,23(3):A34-A42.
[2]LAUBSCHA,SABATHIL M,BAUR J,et al..High-power and high-efficiency In Ga N-based light emitters[J].IEEE Trans.Electron.Dev.,2009,57(1):79-87.
[3]HORIUCHI N.Light-emitting diodes:natural white light[J].Nat.Photon.,2011,4(11):738-743.
[4]SOH C B,CHUA S J,LIM H F,et al..Identification of deep levels in Ga N associated with dislocations[J].J.Phys.Condens.Matter,2004,16(34):6305-6315.
[5]LE L C,ZHAO D G,JIANG D S,et al..Carriers capturing of V-defect and its effect on leakage current and electroluminescence in In Ga N-based light-emitting diodes[J].Appl.Phys.Lett.,2012,101(25):252110-1-4.
[6]HANGLEITER A,HITZEL F,NETZEL C,et al..Suppression of nonradiative recombination by V-shaped pits in Ga In N/Ga N quantum wells produces a large increase in the light emission efficiency[J].Phys.Rev.Lett.,2005,95(12):127402-1-4.
[7]NETZEL C,BREMERS H,HOFFMANN L,et al..Emission and recombination characteristics of Ga1-xInxN/Ga N quantum well structures with nonradiative recombination suppression by V-shaped pits[J].Phys.Rev.B:Condens.Matter Mater.Phys.,2007,76(15):155322-1-6.
[8]CHOY H,KIM J Y,KIM J,et al..Quantum efficiency affected by localized carrier distribution near the V-defect in Ga N based quantum well[J].Appl.Phys.Lett.,2013,103(26):261101-1-4.
[9]KIM J,KIM J,TAK Y,et al..Effect of V-shaped pit size on the reverse leakage current of In Ga N/Ga N light-emitting diodes[J].IEEE Electron Dev.Lett.,2013,34(11):1409-1411.
[10]KIM J,CHO Y H,KO D S,et al..Influence of V-pits on the efficiency droop in In Ga N/Ga N quantum wells[J].Opt.Express,2014,22(S3):A857-A866.
[11]HAN S H,LEE D Y,SHIM H W,et al..Improvement of efficiency and electrical properties using intentionally formed Vshaped pits in In Ga N/Ga N multiple quantum well light-emitting diodes[J].Appl.Phys.Lett.,2013,102(25):251123-1-4.
[12]WU X M,LIU J J,QUAN Z J,et al..Electroluminescence from the sidewall quantum wells in the V-shaped pits of In Ga N light emitting diodes[J].Appl.Phys.Lett.,2014,104(22):221101-1-5.
[13]LI Y F,YUN F,SU X L,et al..Deep hole injection assisted by large V-shape pits in In Ga N/Ga N multiple-quantumwells blue light-emitting diodes[J].J.Appl.Phys.,2014,116(12):123101-1-6.
[14]QUAN Z J,WANG L,ZHENG C D,et al..Roles of V-shaped pits on the improvement of quantum efficiency in In Ga N/Ga N multiple quantum well light-emitting diodes[J].J.Appl.Phys.,2014,116(18):181101-1-3.
[15]QUAN Z J,LIU J L,FANG F,et al..A new interpretation for performance improvement of high-efficiency vertical blue light-emitting diodes by In Ga N/Ga N superlattices[J].J.Appl.Phys.,2015,118(19):193102-1-6.
[16]WU X M,LIU J L,JIANG F Y.Hole injection from the sidewall of V-shaped pits into c-plane multiple quantum wells in In Ga N light emitting diodes[J].J.Appl.Phys.,2015,118(16):164504-1-4.
[17]LI C K,WU C K,HSU C C,et al..3D numerical modeling of the carrier transport and radiative efficiency for In Ga N/Ga N light emitting diodes with V-shaped pits[J].AIP Adv.,2016,6(5):055208-1-10.
[18]ZHOU S J,LIU X T.Effect of V-pits embedded In Ga N/Ga N superlattices on optical and electrical properties of Ga Nbased green light-emitting diodes[J].Phys.Stat.Sol.(a),2017,214(5):1600782-1-5.
[19]QUAN Z J,LIU J L,FANG F,et al..Effect of V-shaped pit area ratio on quantum efficiency of blue In Ga N/Ga N multiple-quantum well light-emitting diodes[J].Opt.Quant.Electron.,2016,48(3):195-1-8.
[20]SILVACO Inc.ATLAS[EB/OL].[2017-09-09].http://www.silvaco.com.
[21]SILVAC Inc.ATLAS Users Manual 2012[EB/OL].(2012-03-20).http://www.silvaco.com.
[22]FIORENTINI V,BERNARDINI F,AMBACHER O.Evidence for nonlinear macroscopic polarization inⅢ-V nitride alloy heterostructures[J].Appl.Phys.Lett.,2002,80(7):1204-1206.
[23]RENNER F,KIESEL P,DOHLER G H,et al..Quantitative analysis of the polarization fields and absorption changes in In Ga N/Ga N quantum wells with electroabsorption spectroscopy[J].Appl.Phys.Lett.,2002,81(3):490-492.
[24]ZHANG H,MILLER E J,YU E T,et al..Measurement of polarization charge and conduction-band offset at InxGa1-xN/Ga N heterojunction interfaces[J].Appl.Phys.Lett.,2004,84(23):4644-1-3.
[25]RINKEP,DELANEY K T,VAN DE WALLE C G.Auger recombination rates in nitrides from first principles[J].Appl.Phys.Lett.,2009,94(19):191109-1-4.
[26]RYU H Y,LEE S H.Simulation of the effects of Al Ga N electron-blocking layers on the characteristics of In Ga N blue lightemitting diodes[J].J.Korean Phys.Soc.,2012,61(9):1395-1399.
[27]SHEN Y C,MUELLER G O,WATANABE S,et al..Auger recombination in In Ga N measured by photoluminescence[J].Appl.Phys.Lett.,2007,91(14):141101-1-3.
[28]CHEN J R,WU Y C,LING S C,et al..Investigation of wavelength-dependent efficiency droop in In Ga N light-emitting diodes[J].Appl.Phys.B,2010,98(4):779-789.
[29]LIU C,REN Z W,CHEN X,et al..Study of In Ga N/Ga N light emitting diodes with step-graded electron blocking layer[J].IEEE Photon.Technol.Lett.,2014,26(2):134-137.
[30]LAHOURCADEL,PERNOT J,WIRTHMLLER A,et al..Mg doping and its effect on the semipolar Ga N(11 22)growth kinetics[J].Appl.Phys.Lett.,2009,95(17):171908-1-3.
[31]ZHANG Y P,ZHANG Z H,LIU W,et al..Nonradiative recombination--critical in choosing quantum well number for In Ga N/Ga N light-emitting diodes[J].Opt.Express,2015,23(3):A34-A42.
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