超晶格电子阻挡层周期数对AlGaN基深紫外发光二极管性能的影响  

Influence of period number of superlattice electron barrier layer on the performance of AlGaN-based deep ultraviolet LED

作　　者：刘举 曹一伟 吕全江 杨天鹏 米亭亭 王小文 刘军林 Liu Ju;Cao Yi-Wei;Lv Quan-Jiang;Yang Tian-Peng;Mi Ting-Ting;Wang Xiao-Wen;Liu Jun-Lin(School of Materials Science and Engineering,Jiangsu University,Zhenjiang 212013,China;Epitop Optoelectronic Co.,Ltd.,Ma’anshan 243000,China;Ma’anshan Jason Semiconductor Co.,Ltd.,Ma’anshan 243000,China)

机构地区：[1]江苏大学材料科学与工程学院,镇江212013 [2]圆融光电科技股份有限公司,马鞍山243000 [3]马鞍山杰生半导体有限公司,马鞍山243000

出　　处：《物理学报》2024年第12期393-401,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62374076,62104085);江苏省双创团队项目(批准号:JSSCTD202146)资助的课题。

摘　　要：在AlGaN基深紫外发光二极管(DUV-LEDs)中设计了具有不同周期数的超晶格电子阻挡层(SL-EBL)结构,研究了SL-EBL周期数对DUV-LEDs发光效率、I-V特性、可靠性及有源区载流子复合机制的影响.研究结果表明,随着SL-EBL的周期数增加,DUV-LEDs的光输出功率(LOP)、外量子效率(EQE)和电光转换效率(WPE)均呈先上升后下降的趋势,同时泄漏电流减小,可靠性提升.当周期数为7时(厚度为28 nm),DUV-LEDs裸芯的EQE和WPE均达到最大值,在7.5 mA注入电流下分别为3.5%和3.2%.能带模拟结果证明了增加SL-EBL周期数可以有效提升电子势垒高度,而几乎不改变空穴势垒高度.然而,当SL-EBL超过一定厚度时,抑制了空穴向有源区的注入,导致EQE和WPE随SL-EBL周期数变化出现拐点.研究了SL-EBL周期数对DUV-LEDs载流子复合机制的影响,发现增加SL-EBL周期数可以有效地降低有源区内载流子非辐射复合.The development of AlGaN-based deep ultraviolet light emitting diodes(DUV-LEDs)is currently limited by poor external quantum efficiency(EQE)and wall-plug efficiency(WPE).Internal quantum efficiency(IQE),as an important component of EQE,plays a crucial role in improving the performance of DUV-LEDs.The IQE is related to the carrier injection efficiency and the radiation recombination rate in the active region.In order to improve the IQE of AlGaN-based DUV-LEDs,this work proposes a scheme to optimize the period number of superlattice electron barrier layer(SL-EBL)to achieve better carrier injection efficiency and confinement capability.The effect of the period number of SL-EBL on the luminous efficiency,reliability and carrier recombination mechanism of AlGaN-based DUV-LEDs with an emission wavelength of 273 nm are investigated.The experimental results show that the light output power(LOP),external quantum efficiency(EQE)and wallplug efficiency(WPE)of the DUV-LEDs tend to first increase and then decrease with the period number of SLEBL increasing,while the leakage current decreases and the reliability is enhanced.The maximum EQE and WPE of the DUV-LED are 3.5% and 3.2%,respectively,at an injection current of 7.5 mA when the period number of SL-EBL is fixed at 7(the thickness is 28 nm).Meanwhile,the numerical simulation results show that the electron potential barrier height is enhanced with the period number of SL-EBL increasing,and the variation of the hole potential barrier height is negligible.Therefore,increasing the period number of SL-EBL is beneficial to shielding the dislocations and suppressing the leakage of electrons into the p-type layer,which improves the luminous efficiency and reliability of DUV-LEDs.However,when the period number of SL-EBL exceeds 7,the excessively thick hole potential barrier prevents the holes from entering into the activation region and reduces the radiative recombination efficiency.Therefore,EQE and WPE will show an inflection point with the variation of the period number of SL-E

关 键 词：深紫外发光二极管 电子阻挡层 可靠性 外量子效率 

分 类 号：TN312.8[电子电信—物理电子学]