Carrier Recombination Processes in Gallium Indium Phosphide Nanowires.
Carrier Recombination Processes in Gallium Indium Phosphide Nanowires.
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DOI：
10.1021/acs.nanolett.7b01159
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发表时间：
2017-06
期刊：
影响因子：
10.8
通讯作者：
Wei Zhang;Xulu Zeng;Xiaojun Su;Xianshao Zou;P. Mante;M. Borgström;A. Yartsev
中科院分区：
文献类型：
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作者：
Wei Zhang;Xulu Zeng;Xiaojun Su;Xianshao Zou;P. Mante;M. Borgström;A. Yartsev
了解GaxIn1-XP NWS中光生载流子的复合和光导动力学对于它们的光电应用是至关重要的。在这封信中，我们研究了一系列具有不同Ga组分的GaxIn1-XPNW。利用时间分辨的光致发光、飞秒瞬时吸收和时间分辨的太赫兹透射率测量，研究了NWS中光生电荷的辐射复合和非辐射复合以及光导动力学。我们的结论是，辐射复合动力学受空穴捕获的限制，而电子在非辐射复合之前是高度可移动的。我们还解决了光生电子的迁移率在陷阱态分布中被分配给电子陷阱和去陷阱的逐渐降低的问题。我们发现，电荷的非辐射复合比光致发光信号的衰减慢得多。进一步地，我们得出结论：随着Ga组分的增加，GaIn1-XP NWS中电子和空穴的俘获以及非辐射复合都变得更快。我们估算了GaxIn1-XPNW的早期电子迁移率，发现由于X谷中电子的贡献，它强烈地依赖于Ga的组成。
Understanding of recombination and photoconductivity dynamics of photogenerated charge carriers in GaxIn1-xP NWs is essential for their optoelectronic applications. In this letter, we have studied a series of GaxIn1-xP NWs with varied Ga composition. Time-resolved photoinduced luminescence, femtosecond transient absorption, and time-resolved THz transmission measurements were performed to assess radiative and nonradiative recombination and photoconductivity dynamics of photogenerated charges in the NWs. We conclude that radiative recombination dynamics is limited by hole trapping, whereas electrons are highly mobile until they recombine nonradiatively. We also resolve gradual decrease of mobility of photogenerated electrons assigned to electron trapping and detrapping in a distribution of trap states. We identify that the nonradiative recombination of charges is much slower than the decay of the photoluminescence signal. Further, we conclude that trapping of both electrons and holes as well as nonradiative recombination become faster with increasing Ga composition in GaxIn1-xP NWs. We have estimated early time electron mobility in GaxIn1-xP NWs and found it to be strongly dependent on Ga composition due to the contribution of electrons in the X-valley.