Composition-dependent ultra-high photoconductivity in ternary CdS x Se1-x nanobelts as measured by optical pump-terahertz probe spectroscopy

被引：24

作者：

Liu, Hongwei ^{[1
,2
]}

Lu, Junpeng ^{[1
]}

Zheng, Minrui ^{[1
]}

Tang, Sing Hai ^{[1
]}

Zhang, Xinhai ^{[2
]}

Sow, Chorng Haur ^{[1
]}

机构：

[1] Natl Univ Singapore, Dept Phys, Singapore 117542, Singapore

[2] ASTAR, Inst Mat Res & Engn, Singapore 117602, Singapore

来源：

NANO RESEARCH | 2013年 / 6卷 / 11期

关键词：

nanomaterials and nanostructures; optical materials; photoconductivity; ternary alloys; THz spectroscopy; TRANSIENT PHOTOCONDUCTIVITY; CDSXSE1-X NANOBELTS; CARRIER RELAXATION; NANOWIRES; DYNAMICS; GAAS; CONDUCTIVITY; PHOTODETECTOR; NANOPARTICLES; LIFETIME;

D O I：

10.1007/s12274-013-0359-x

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We employ optical pump-terahertz probe spectroscopy to investigate the composition-dependent photoconductivity in ternary CdS (x) Se1-x nanobelts. The observed carrier dynamics of CdS nanobelts display much shorter lifetime than those of ternary CdS (x) Se1-x nanobelts. This indicates the implementation of CdS nanobelts as ultrafast switching devices with a switching speed potentially up to 46.7 GHz. Surprisingly, ternary CdS (x) Se1-x nanobelts are found to exhibit much higher photoconductivity than binary CdS and CdSe. This is attributed to the higher photocarrier densities in ternary compounds. In addition, the presence of Se in samples resulted in prominent CdSe-like transverse optical (TO) phonon modes due to electron-phonon interactions. The strength of this mode shows a large drop upon photoexcitation but recovers gradually with time. These results demonstrated that growth of ternary nanostructures can be utilized to alleviate the high surface defect density in nanostructures and improve their photoconductivity.

引用

页码：808 / 821

页数：14

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