InGaN/GaN多量子阱LED载流子泄漏与温度关系研究
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摘要
通过测量光电流,直接观察了InGaN/GaN量子阱中载流子的泄漏程度随温度升高的变化关系。当LED温度从300K升高到360K时,在相同的光照强度下,LED的光电流增大,说明在温度上升之后,载流子从量子阱中逃逸的数目更多,即载流子泄漏比例增大。同时,光电流的增大在激发密度较低的时候更为明显,而且光电流随温度的增加幅度与激发光子的能量有关。用量子阱-量子点复合模型能很好地解释所观察到的实验现象。实验结果直接证明,随着温度的升高,InGaN/GaN量子阱中的载流子泄漏将显著增加,而且在低激发密度下这一效应更为明显。温度升高导致的载流子泄漏增多是InGaN多量子阱LED发光效率随温度升高而降低的重要原因。
By measuring the photocurrent,we directly observed the relationship between the degree of carrier leakage and the temperature in InGaN multiple quantum wells. When LED's working temperature rises from room temperature to 360 K,the photocurrent increases under the same light intensity. The increase of the sample's photocurrent means larger amount of carrier leakage when the temperature rises. At the same time,it is found that the carriers leak more in a lower density,and the increase of photocurrent is related to the emission photon energy. The model of quantum wellquantum dot can explain the phenomena observed in the experiment,such as the rise of temperature shows little influence on carrier leakage when the excitation light wavelength is relatively short,and causes more carrier leakage when the emission light wavelength is longer. Also,this model can well explain that the carriers leak more in a lower density and leak less in a higher density when the temperature rises. The experiment results suggest that the carrier leakage is the dominant mechanism for T-droop effect when the temperature rises from 300 to 360 K.
By measuring the photocurrent,we directly observed the relationship between the degree of carrier leakage and the temperature in InGaN multiple quantum wells. When LED's working temperature rises from room temperature to 360 K,the photocurrent increases under the same light intensity. The increase of the sample's photocurrent means larger amount of carrier leakage when the temperature rises. At the same time,it is found that the carriers leak more in a lower density,and the increase of photocurrent is related to the emission photon energy. The model of quantum wellquantum dot can explain the phenomena observed in the experiment,such as the rise of temperature shows little influence on carrier leakage when the excitation light wavelength is relatively short,and causes more carrier leakage when the emission light wavelength is longer. Also,this model can well explain that the carriers leak more in a lower density and leak less in a higher density when the temperature rises. The experiment results suggest that the carrier leakage is the dominant mechanism for T-droop effect when the temperature rises from 300 to 360 K.
引文
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[22]SUN Q,YAN W,FENG M X,et al..Ga N-on-Si blue/white LEDs:epitaxy,chip,and package[J].J.Semicond.,2016,37(4):044006.
[23]SANTI C D,MENEGHINI M,GRASSAM L,et al..Role of defects in the thermal droop of In Ga N-based light emitting diodes[J].J.Appl.Phys.,2016,119(9):094501.
[2]金尚忠,张树生,侯民贤.白光照明LED灯温度特性的研究[J].光源与照明,2004(4):6-8.JIN S Z,ZHANG S S,HOU M X.The research of temperature characteristic in white light LED[J].Lamps Light.,2004(4):6-8.(in Chinese)
[3]CAO K W,FU B L,LIU Z,et al..Anomalous luminescence efficiency enhancement of short-term aged Ga N-based blue light-emitting diodes[J].J.Semicond.,2016,37(1):014008.
[4]KIM M H,SCHUBERT M F,DAI Q,et al..Origin of efficiency droop in Ga N-based light-emitting diodes[J].Appl.Phys.Lett.,2007,91(18):183507-1-3.
[5]MEYAARD D S,LIN G B,SHAN Q F,et al..Asymmetry of carrier transport leading to efficiency droop in Ga In N based light-emitting diodes[J].Appl.Phys.Lett.,2011,99(25):251115-1-2.
[6]MUKAI T,YAMADA M,NAKAMURA S.Characteristics of In Ga N-based UV/blue/green/amber/red light-emitting diodes[J].Jpn.J.Appl.Phys.,1999,38(7A):3976-3981.
[7]YANG Y,CAO X A,YAN C H.Investigation of the nonthermal mechanism of efficiency rolloff in In Ga N light-emitting diodes[J].IEEE Trans.Electron Dev.,2008,55(7):1771-1775.
[8]HADER J,MOLONEY J V,KOCH S W,et al..Density-activated defect recombination as a possible explanation for the efficiency droop in Ga N-based diodes[J].Appl.Phys.Lett.,2010,96(22):221106-1-3.
[9]HADER J,MOLONEY J V,KOCH S W.Temperature-dependence of the internal efficiency droop in Ga N-based diodes[J].Appl.Phys.Lett.,2011,99(18):181127-1-3.
[10]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.
[11]MEYAARD D S,SHAN Q F,CHO J,et al..Temperature dependent efficiency droop in Ga In N light-emitting diodes with different current densities[J].Appl.Phys.Lett.,2012,100(8):081106-1-3.
[12]HUH C,SCHAFF W J,EASTMAN L F,et al..Temperature dependence of performance of In Ga N/Ga N MQW LEDs with different indium compositions[J].IEEE Electron Dev.Lett.,2004,25(2):61-63.
[13]JIANG R,LU H,CHEN D J,et al.Temperature-dependent efficiency droop behaviors of Ga N-based green light-emitting diodes[J].Chin.Phys.B,2013,22(4):047805-1-4.
[14]PLOCH N L,EINFELDT S,FRENTRUP M,et al..Solar blind UV region and UV detector development objectives[J].Semicond.Sci.Technol.,2013,28(12):2558-2562.
[15]JANI O,FERGUSON I,HONSBERG C,et al..Design and characterization of Ga N/In Ga N solar cells[J].Appl.Phys.Lett.,2007,91(13):132117-1-3.
[16]LANG J R,YOUNG N G,FARRELL R M,et al..Carrier escape mechanism dependence on barrier thickness and temperature in In Ga N quantum well solar cells[J].Appl.Phys.Lett.,2012,101(18):181105-1-5.
[17]SILVACO INC.ATLAS User's Manual 2012[EB/OL].(2013-10-02).http://www.silvaco.com.
[18]LAI K Y,LIN G J,CHEN C Y,et al..Origin of hot carriers in In Ga N-Based quantum-well solar cells[J].IEEE Electron Dev.Lett.,2011,32(2):179-181.
[19]O'DONNELL K P,MARTIN R W,MIDDLETON P G.Origin of luminescence from In Ga N diodes[J].Phys.Rev.Lett.,1999,82(1):237-240.
[20]KRESTNIKOV I L,LEDENTSOV N N,HOFFMANN A,et al..Quantum dot origin of luminescence in In Ga N-Ga N structures[J].Phys.Rev.B,2002,66(15):155310-1-5.
[21]CHANG H J,CHEN C H,CHEN Y F,et al..Direct evidence of nanocluster-induced luminescence in In Ga N epifilms[J].Appl.Phys.Lett.,2005,86(86):021911-1-3.
[22]SUN Q,YAN W,FENG M X,et al..Ga N-on-Si blue/white LEDs:epitaxy,chip,and package[J].J.Semicond.,2016,37(4):044006.
[23]SANTI C D,MENEGHINI M,GRASSAM L,et al..Role of defects in the thermal droop of In Ga N-based light emitting diodes[J].J.Appl.Phys.,2016,119(9):094501.