Transient absorption spectroscopy with attosecond EUV pulses on binary and ternary solar cell semiconductor systems for the investigations of their charge carrier dynamics

半导体系统是当今非常重要的材料，因为它们的物理性质允许广泛的应用，如二极管、光探测器、光调制器、高速电子器件或太阳能电池设备中的发光。对基本电子过程的了解是其继续进一步发展的先决条件。几十年来，时间分辨光谱学的目标是获得这些过程。研究揭示了时间尺度，其中最慢的过程发生在皮秒，最快的过程发生在阿秒时间尺度上。阿秒瞬变吸收光谱学是从年轻的阿秒科学领域出现的，代表着今天一个非常强大的工具，即使是利用单个孤立的阿秒脉冲来研究物质中最快的过程。这项测量技术首次揭示了最常见的半导体材料硅的导带中阿秒电子-电子散射过程的时间分辨实验证据。从一次(Si，Ge)到二元(GaAs)再到三元(AlGaAs)半导体系统的方法允许提高太阳能电池设备的效率，因为可以管理更精确的太阳光谱调谐。该研究项目利用阿秒暂态吸收光谱来研究二元和三元半导体系统中的载流子动力学，以获得它们的基本过程。深入的研究和对基本载流子动力学的了解，例如电荷分离和电荷迁移，可能有助于改进层结构或设计，并最终提高太阳能电池的效率。因此，计划中的研究项目可以通过将阿秒测量技术应用于非常重要的半导体系统，提供新的太阳能电池基础物理，并为非常重要的可再生能源领域做出巨大贡献。

Semiconductor systems are very important materials today, since their physical properties allow a wide range of applications such as light emitting in diodes, light detectors, optical modulators, high speed electronics or solar cell devices. The knowledge of the underlying electronic processes is the prerequisite for their continuous further development. For decades time-resolved spectroscopy aims for the access to those processes. Investigations revealed the timescales where the slowest processes occur on the picosecond and the fastest on the attosecond timescale. Attosecond transient absorption spectroscopy has emerged from the young field of attosecond science representing today a very powerful tool to study even the fastest processes in matter utilizing single isolated attosecond pulses. This measurement technique revealed the first time-resolved experimental proof of attosecond electron-electron scattering processes in the conduction band of the most common semiconductor material, silicon. The way from primary (Si, Ge) via binary (GaAs) to ternary (AlGaAs) semiconductor systems allowed to increase the efficiency of solar cell devices, since a more accurate tuning to the solar spectrum can be managed. The research project investigates the carrier dynamics in binary and ternary semiconductor systems utilizing attosecond transient absorption spectroscopy to gain access to their fundamental processes. The far-reaching investigation and the knowledge about fundamental charge carrier dynamics, for example charge separation and charge migration, may contribute to improved layer structures or designs and ultimately an increase the efficiency of solar cells. As a consequence the planned research project can, through the application of an attosecond measurement technique to very important semiconductor systems, offer new fundamental physics of solar cells and contribute enormously to the very important field of renewable energies.