蓝光激光器结构中InGaN/GaN多量子阱界面效应的精细光致发光光谱研究  

Fine Photoluminescence Spectroscopic Characterization of Interfacial Effects on Emission Properties of InGaN/GaN Multiple Quantum Wells in a Blue-Light Laser Diode Structure

作　　者：王滔 刘建勋 葛啸天 王荣新[2] 孙钱[2] 宁吉强 郑昌成 WANG Tao;LIU Jian-xun;GE Xiao-tian;WANG Rong-xin;SUN Qian;NING Ji-qiang;ZHENG Chang-cheng(School of Nano-Tech and Nano-Bionics,University of Science and Technology of China,Hefei 230026,China;Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,Suzhou 215123,China;Division of Natural and Applied Sciences,Duke Kunshan University,Kunshan 215316,China)

机构地区：[1]中国科学技术大学纳米技术与纳米仿生学院,安徽合肥230026 [2]中国科学院苏州纳米技术与纳米仿生研究所,江苏苏州215123 [3]昆山杜克大学自然与应用科学学部,江苏昆山215316

出　　处：《光谱学与光谱分析》2022年第4期1179-1185,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(11974378,11874390);中国科学院战略性先导科技专项(XDB43000000,XDB43020200);中国科学院前沿科学重点研究计划(QYZDB-SSW-JSC014,ZDBS-LY-JSC040);江苏高校“青蓝工程”项目资助。

摘　　要：金属有机化学气相沉积(MOCVD)方法制备InGaN/GaN多量子阱结构时,在GaN势垒层生长的N_(2)载气中引入适量H_(2),能够有效改善阱/垒界面质量从而提升发光效率。本工作利用光致发光(PL)光谱技术,对蓝光激光器结构中的InGaN/GaN多量子阱的发光性能进行了精细的光谱学测量与表征,研究了通H_(2)生长对量子阱界面的调控效应及其发光效率提升的物理机制。室温PL光谱结果显示,GaN势垒层生长载气中引入2.5%的H_(2)使InGaN/GaN多量子阱的发光效率提升了75%、发光峰的峰位蓝移了17 meV、半峰宽(FWHM)减小了10 meV。通过功率依赖的PL光谱特征分析,我们对InGaN/GaN量子阱中的量子限制Stark效应(QCSE)和能带填充(Band Filling)效应进行了清晰的辨析,发现了发光峰峰位和峰宽的光谱特征主要受QCSE效应影响,H_(2)的引入能够大幅度降低QCSE效应,并且确定了QCSE效应被完全屏蔽情况下的发光峰能量为2.75 eV。温度依赖的PL光谱数据揭示了通H_(2)生长量子阱结构中显著减弱的载流子局域化行为,显示界面质量提高有效降低了限制势垒的能量波动,从而导致更窄的发光峰半峰宽。PL光谱强度随温度的变化规律表明,通H_(2)生长并不改变量子阱界面处的非辐射复合中心的物理本质,却能够显著减少非辐射复合中心的密度,有助于提升量子阱的发光效率。通过时间分辨PL光谱分析,发现通H_(2)生长会导致量子阱结构中更短的载流子辐射复合寿命,但不影响非辐射复合寿命。载流子复合寿命的变化特征进一步确认了通H_(2)生长对量子阱结构中QCSE效应和非辐射复合中心的影响规律。综合所有PL光谱分析结果,我们发现通H_(2)生长能够提高InGaN/GaN多量子阱的界面质量、显著减弱应力效应(更弱的QCSE效应)、降低限制势垒的能量波动以及减少界面处非辐射复合中心的密度,从而显著提升量子阱的发光效率。该研究工�In growing InGaN/GaN multiple quantum wells(MQWs) with the technique of metal-organic chemical vapor deposition(MOCVD),the introduction of an appropriate amount of H_(2) into the N_(2) carrier gas for the growth of the GaN barrier layers can effectively improve the crystalline quality of the well/barrier interface and therefore enhance the luminescence efficiency of the quantum wells.In this work,we carried out detailed photoluminescence(PL) spectroscopic measurements on the luminescence properties of InGaN/GaN MQWs in the device structure for blue-light laser diodes,and the effects of H_(2) in the carrier gas for GaN barrier growth on the MQWs,including the improved interface quality,the enhanced luminescence and the underlying mechanisms,have been investigated.The PL spectra of the InGaN/GaN MQWs acquired at room temperature reveal that the introduction of 2.5% H_(2) in the N_(2) carrier gas leads to increased emission efficiency by 75%,blue-shifted peak energy by 17 meV,and narrowed full width at half maximum(FWHM) by 10 meV.With the PL spectra measured at varied excitation powers,the quantum-confined Stark effect(QCSE) and band-filling effect on the emission performance of the MQWs have been distinguished,and the QCSE effect is found to dominantly determine the emission energy and width,which can be effectively reduced by the introduction of H_(2).Upon the complete screening of the QCSE effect,the peak energy of the MQWs emission is located at 2.75 eV.The dependence of the PL spectra on temperature indicates that the introduced H_(2) in the carrier gas can also reduce the carrier localization effect and narrow the energy fluctuation of the well potential,which leads to the narrowed PL spectral width in the samples grown with the mixture of H_(2)/N_(2) carrier gas.The variation of the PL intensity with respect to temperature reveals that the physical nature of the nonradiative recombination centers at the interface is not influenced by the introduction of H_(2),but the amount of these centers is greatly reduce

关 键 词：INGAN/GAN多量子阱 光致发光光谱 量子限制Stark效应 载流子局域化 载流子复合寿命 

分 类 号：N34[自然科学总论]