摘要:
InGaAs/AlGaAs量子阱是中波量子阱红外探测器件最常用的材料体系,本文以结构为2.4 nm In0.35Ga0.65As/40 nm Al0.34Ga0.66As的多量子阱材料为研究对象,利用分子束外延生长,固定InGaAs势阱的生长温度(465℃),然后依次升高分别选取465,500,545,580℃生长AlGaAs势垒层,从而获得四个不同的多量子阱样品.通过荧光光谱以及X射线衍射测试系统分析了势垒层生长温度对InGaAs量子阱发光和质量的影响,并较准确地给出了量子阱大致的温致弛豫轨迹:465—500℃,开始出现相分离,但缺陷水平较低,属弹性弛豫阶段;500—545℃,相分离加剧并伴随缺陷水平的上升,属弹性弛豫向塑性弛豫过渡阶段;545—580℃,相分离以及缺陷水平急剧上升,迅速进入塑性弛豫阶段,尤其是580℃时,量子阱的材料质量被严重破坏.
Abstract:
The InGaAs/AlGaAs quantum wells have been extensively applied to quantum well infrared photodetector of mid-wavelength. In this letter, four samples of 2.4 nm In0.35Ga0.65As/40 nm Al0.34Ga0.66As multi-quantum wells are grown by molecular beam epitaxy with the InGaAs wells growing all at a temperature of 465 ℃℃ but the AlGaAs wells growing at temperatures of 465 ℃, 500 ℃, 545 ℃, and 580 ℃ respectively. The dependence of InGaAs quantum well strain relaxation on the AlGaAs growth temperature is systematically studied by photoluminescence spectroscopy and X-ray diffraction and then the thermal-induced relaxations of three key-stages are clearly observed in the following temperature ranges. 1) 465–500 ℃ for the stage of elastic relaxation: the phase separation begins to take place with a low defect density;2) 500–545 ℃ for the transition stage from elastic relaxation to plastic relaxation: the phase separation will be further intensified with defect density increasing; 3) 545–580 ℃ for the fast stage dominated by elastic relaxation and the defect density will sharply increase. Especially when AlGaAs temperature increases to 580 ℃, a very serious plastic relaxation will take place and the InGaAs quantum well will be dramatically destroyed.
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