摘要
利用磁控溅射和金属有机化学气相沉积方法在c面蓝宝石衬底上生长了深紫外Al_(0.38)Ga_(0.62)N/Al_(0.55)Ga_(0.45)N多量子阱结构,并对其荧光(PL)谱进行了测量。其PL谱的激发密度依赖性测量结果表明,该量子阱的辐射过程包含了局域载流子的散射、极化场的屏蔽和局域态的填充效应;其PL谱的温度依赖性测量结果则表明,该量子阱的辐射过程包含了局域载流子的弛豫、局域载流子的热激发和自由载流子的常规热化效应。这个现象(即多种辐射复合过程的存在)在低温和弱激发测试条件下尤为显著,并且表现出该量子阱结构具有显著的局域深度非均一性和载流子的局域效果,是浅局域载流子的散射效应和深局域态的载流子填充效应共同作用所致。在较低的温度范围内,随着温度升高,该量子阱的辐射过程是由浅局域载流子的弛豫效应和深局域载流子的热激发效应共同作用的结果。这些行为被归因于阱宽起伏所诱发的局域深度的非均一性和载流子的局域效果。
A deep-ultraviolet Al_(0.38)Ga_(0.62)N/Al_(0.55)Ga_(0.45)N multiple quantum well(MQW)structure was grown on a c-plane sapphire substrate using magnetron sputtering and metal organic chemical vapor deposition(MOCVD)meth⁃ods,while the excitation density and temperature dependences of its photoluminescence(PL)spectrum were mea⁃sured in the wide excitation density(0.1-500 kW/cm^(2))and temperature(6-300 K)ranges.The excitation densitydependent peak energies and line widths of the PL peak PW from the MQWs measured at the low temperature of 6 K show that,within the low excitation density range(≤10 kW/cm^(2)),the PW line width remains almost constant,while its peak energy remains almost constant first(≤0.5 kW/cm^(2))and then gradually increases with increasing the excita⁃tion density,indicating that the excitation density-dependent emission process of the MQWs is dominated first by the combined effect of the scattering effect of high-energy(shallow)-localized carriers and filling effect of low-energy(deep)-localized states,and then by the combined effect of the filling effect of medium-energy(medium-depth)-localized states and Coulomb screening effect of free carriers.However,within the high excitation density range(>10 kW/cm^(2)),both the PW peak line width and peak energy increase significantly,indicating that the excitation density-dependent emission process of the MQWs is dominated by the filling effect of high-energy-localized states.On the other hand,the temperature-dependent peak energies and line widths of the PW peak measured at the low exci⁃tation density of 0.1 kW/cm^(2)show that,within the low temperature range(≤140 K),the PW line width remains al⁃most constant,while its peak energy monotonically decreases,indicating that the temperature-dependent emission process of the MQWs may be dominated by the combined effect of the relaxation of high-energy-localized carriers and thermal excitation of low-energy-localized carriers;within the high temperature range(>140 K),PW peak line width increases s
作者
邓建阳
贺龙飞
武智波
李睿
徐明升
王成新
徐现刚
冀子武
DENG Jianyang;HE Longfei;WU Zhibo;LI Rui;XU Mingsheng;WANG Chengxin;XU Xiangang;JI Ziwu(Institute of Novel Semiconductors,School of Microelectronics,Shandong University,Jinan 250100,China;Institute of Semiconductor Research,Guangdong Academy of Sciences,Guangzhou 510650,China;Shandong Inspur Huaguang Optoelectronics Co.,Ltd.,Weifang 261061,China)
出处
《发光学报》
EI
CAS
CSCD
北大核心
2023年第11期1974-1980,共7页
Chinese Journal of Luminescence
基金
广州市基础研究计划(202201010679)
国家自然科学基金(52272157)。
