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Spatial visualization of electron wavefunctions and acoustic phonon transduction in semiconductor quantum wells and related applications

半导体量子阱中电子波函数和声声子传导的空间可视化及相关应用

基本信息

批准号：
13852006
负责人：
WRIGHT Oliver B.
金额：
$ 79.12万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (S)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2005
项目状态：
已结题

项目摘要

1)THz phonon generation and detection experiments were done on 2-well and 3-well GaAs/GaAlAs samples with surface-absorbed probe optical pulses and wavelength-tuned pump optical pulses. These first spectroscopic experiments in the domain of picosecond acoustics (up to 0.3 THz) were successfully treated with theoretical models to describe the phonon generation and detection in these multilayers. We also characterized the spectral generation efficiency.2)Improvements in temporal and spatial resolution were achieved using shorter (〜400 fs) optical pulses to demonstrate detection at frequencies up to 0.5 THz. We also developed a new optical-polarization-sensitive oblique-incidence technique, tested on Cr, to separate different signal contributions, and modelled the phonon pulse shapes for this sample.3)A Novel ultrafast Sagnac interferometer was developed for picosecond phonon detection with 1 μm spatial resolution, applicable to semiconductors, involving a single focusing objective.4)Bulk GaAs picosecond acoustics was implemented to help interpret the quantum well results, we investigated ultrafast phonon generation in 3 different GaAs samples. We demonstrate the generation of picosecond shear pulses using anisotropic cuts and pulse-broadening by electron diffusion.5)A novel detection scheme based photoluminescence was extensively tested on quantum well samples. The results show that we require a higher detection sensitivity to achieve detection of phonon -pulses detection within a quantum well rather than at the surface.

1)采用表面吸收探针光脉冲和波长调谐泵浦光脉冲在2井和3井GaAs/GaAlAs样品上进行太赫兹声子产生和检测实验。这些皮秒声学（高达 0.3 THz）领域的首次光谱实验成功地用理论模型进行了处理，以描述这些多层中的声子生成和检测。我们还表征了光谱生成效率。2）使用更短（约 400 fs）的光脉冲实现了时间和空间分辨率的改进，以证明频率高达 0.5 THz 的检测。我们还开发了一种新的光学偏振敏感斜入射技术，在 Cr 上进行了测试，以分离不同的信号贡献，并对该样品的声子脉冲形状进行了建模。3) 开发了一种新型超快 Sagnac 干涉仪，用于皮秒声子检测，具有 1 μm 空间分辨率，适用于半导体，涉及单个聚焦物镜。4) 体质 GaAs 皮秒声学被实现为了帮助解释量子阱结果，我们研究了 3 种不同 GaAs 样品中的超快声子产生。我们演示了使用各向异性切割和电子扩散脉冲展宽来生成皮秒剪切脉冲。5)在量子阱样品上广泛测试了一种基于光致发光的新颖检测方案。结果表明，我们需要更高的检测灵敏度来实现量子阱内而不是表面的声子脉冲检测。