非均匀GaAs/AlGaAs量子阱红外探测器材料表征和器件性能研究

Study on material characterization and device performance of nonuniform GaAs/AlGaAs quantum well infrared detectors

本文利用分子束外延(MBE)技术成功生长了GaAs/AlGaAs非均匀量子阱红外探测器材料,并对相关微结构作了细致表征。分析比较了非均匀量子阱结构和常规量子阱红外探测器性能差异,并对比研究了不同势阱宽度下非均匀量子阱红外探测器的性能变化。通过高分辨透射电子显微镜(HRTEM)结合能谱仪(EDS)对非均匀量子阱红外探测器材料微结构进行了分析,并利用二次离子质谱仪(SIMS)对非均匀势阱掺杂进行了表征。结果表明,该量子阱外延材料晶体质量很好,量子阱结构和掺杂浓度也与设计值符合较好。对于非均匀量子阱红外探测器,通过改变每个阱的掺杂浓度和势垒宽度,可以改变量子阱电场分布,而与传统的均匀量子阱红外探测器相比,其暗电流显著下降(约一个数量级)。在不同阱宽下,非均匀量子阱的跃迁模式发生改变,束缚态到准束缚态跃迁模式下(B-QB)的器件具有较高的黑体响应率以及较低的暗电流。

In this paper,the GaAs/AlGaAs non-uniform quantum well infrared detector material was successfully grown by molecular beam epitaxy(MBE),and the microstructure was characterized in detail.The performance difference between the non-uniform quantum well structure and the conventional quantum well infrared detector is analyzed and compared,and the performance change of the non-uniform quantum well infrared detector under different well widths is comparatively studied.The microstructure of non-uniform quantum well infrared detector materials was analyzed by high resolution transmission electron microscopy(HRTEM)combined with energy dispersive spectroscopy(EDS),and the non-uniform well doping was characterized by secondary ion mass spectrometry(SIMS).The results show that the crystal quality of the non-uniform quantum well epitaxial material is very good,and the non-uniform quantum well structure and doping concentration are also in good agreement with the design values.The results show that for non-uniform quantum well infrared detectors,the electric field distribution of the quantum well can be modulated by changing the doping concentration and barrier width of each well,and the dark current significantly decreases(by about an order of magnitude),compared with traditional uniform quantum well infrared detectors.Moreover,under different well widths,the transition modes of non-uniform quantum wells can change,and the devices with bound state to quasibound state transition modes(B-QB)have better blackbody response and lower dark current.