Microstructure and misfit dislocation behavior in In_xGa_(1-x)As/InP heteroepitaxial materials grown by low pressure metal organic chemical vapor deposition(LP-MOCVD) were analyzed by high resolution transmission electron microscopy(HRTEM), scanning electron microscopy(SEM), atomic force microscopy(AFM), Raman spectroscopy and Hall effect measurements. To optimize the structure of In_(0.82)Ga_(0.18)As/InP heterostructure, the In_xGa_(1-x)As buffer layer was grown. The residual strain of the In_(0.82)Ga_(0.18)As epitaxial layer was calculated. Further, the periodic growth pattern of the misfit dislocation at the interface was discovered and verified. Then the effects of misfit dislocation on the surface morphology and microstructure of the material were studied. It is found that the misfit dislocation of high indium(In) content In_(0.82)Ga_(0.18)As epitaxial layer has significant influence on the carrier concentration.
中科院上海技物所近十年来开展了高性能短波红外InGaAs焦平面探测器的研究。0.9~1.7mm近红外In Ga As焦平面探测器已实现了256×1、512×1、1024×1等多种线列规格,以及320×256、640×512、4000×128等面阵,室温暗电流密度<5 n A/cm^2,室温峰值探测率优于5×10^(12)cm×Hz^(1/2)/W。同时,开展了向可见波段拓展的320×256焦平面探测器研究,光谱范围0.5~1.7mm,在0.8mm的量子效率约20%,在1.0mm的量子效率约45%。针对高光谱应用需求,上海技物所开展了1.0~2.5mm短波红外InGaAs探测器研究,暗电流密度小于10 n A/cm^2@200 K,形成了512×256、1024×128等多规格探测器,峰值量子效率高于75%,峰值探测率优于5×10^(11)cm×Hz^(1/2)/W。
短波红外InGaAs焦平面探测器具有探测率高、均匀性好等优点,在航天遥感、微光夜视、医疗诊断等领域具有广泛应用。近十年来,中国科学院上海技术物理研究所围绕高灵敏度常规波长(0.9~1.7μm)InGaAs焦平面、延伸波长(1.0~2.5μm)InGaAs焦平面以及新型多功能InGaAs探测器取得了良好进展。在常规波长InGaAs焦平面方面,从256×1、512×1元等线列向320×256、640×512、4000×128、1280×10^24元等多种规格面阵方面发展,室温暗电流密度优于5 n A/cm2,室温峰值探测率优于5×10^12cm·Hz1/2/W。在延伸波长InGaAs探测器方面,发展了高光谱高帧频10^24×256、10^24×512元焦平面,暗电流密度优于10 n A/cm^2和峰值探测率优于5×10^11cm·Hz1/2/W@200 K。在新型多功能InGaAs探测器方面,发展了一种可见近红外响应的InGaAs探测器,通过具有阻挡层结构的新型外延材料和片上集成微纳陷光结构,实现0.4~1.7μm宽谱段响应,研制的320×256、640×512焦平面组件的量子效率达到40%@0.5 m、80%@0.8 m、90%@1.55 m;发展了片上集成亚波长金属光栅的InGaAs偏振探测器,其在0°、45°、90°、135°的消光比优于20:1。
