Band Engineering of ErAs:InGaAlBiAs Nanocomposite Materials for Terahertz Photoconductive Switches Pumped at 1550 nm
Band Engineering of ErAs:InGaAlBiAs Nanocomposite Materials for Terahertz Photoconductive Switches Pumped at 1550 nm
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DOI：
10.1002/adfm.202401853
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发表时间：
2024-04
影响因子：
19
通讯作者：
Wilder Acuna;Weipeng Wu;James Bork;M. F. Doty;M. Jungfleisch;Lars Gundlach;J. Zide
中科院分区：
文献类型：
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作者：
Wilder Acuna;Weipeng Wu;James Bork;M. F. Doty;M. Jungfleisch;Lars Gundlach;J. Zide
太赫兹技术有可能在无数领域产生巨大影响，如生物医学科学，光谱学和通信。要使这些应用切实可行，需要高效、可靠和低成本的设备。光电导开关（PCS），能够发射和检测太赫兹脉冲的设备，是一种在电信波长激发（1550 nm）下工作时需要更高效率的技术，以利用该波长提供的优势。ErAs：InGaAs是一种在这种能量下工作的半导体纳米复合材料;然而，由于费米能级位于导带中，因此高暗电阻率是具有挑战性的。为了提高暗电阻率，ErAs：InGaAlBiAs材料被用作PCS检测太赫兹脉冲中的活性材料。ErAs纳米颗粒将载流子寿命降低到短时间分辨率所需的亚皮秒值，而ErAs钉扎主体材料带隙中的有效费米能级。与InGaAs不同，InGaAlBiAs为能带工程提供了足够的自由度，使材料与1550 nm泵浦和带隙深处的费米能级兼容，这意味着低载流子浓度和高暗电阻率。通过结合铝以将导带边缘提升到费米能级和结合铋以保持与1550 nm激发兼容的带隙，能带工程是可能的。
Terahertz technology has the potential to have a large impact in myriad fields, such as biomedical science, spectroscopy, and communications. Making these applications practical requires efficient, reliable, and low‐cost devices. Photoconductive switches (PCS), devices capable of emitting and detecting terahertz pulses, are a technology that needs more efficiency when working at telecom wavelength excitation (1550 nm) to exploit the advantages this wavelength offers. ErAs:InGaAs is a semiconductor nanocomposite working at this energy; however, high dark resistivity is challenging due to a high electron concentration as the Fermi level lies in the conduction band. To increase dark resistivity, ErAs:InGaAlBiAs material is used as the active material in a PCS detecting Terahertz pulses. ErAs nanoparticles reduce the carrier lifetime to subpicosecond values required for short temporal resolution, while ErAs pins the effective Fermi level in the host material bandgap. Unlike InGaAs, InGaAlBiAs offers enough freedom for band engineering to have a material compatible with a 1550 nm pump and a Fermi level deep in the bandgap, meaning low carrier concentration and high dark resistivity. Band engineering is possible by incorporating aluminum to lift the conduction band edge to the Fermi level and bismuth to keep a bandgap compatible with 1550 nm excitation.