Controlled Ambipolar Doping and Gate Voltage Dependent Carrier Diffusion Length in Lead Sulfide Nanowires

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• 作者：Yiming Yang ; Jiao Li ; Hengkui Wu ; Eunsoon Oh ; Dong Yu
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：November 14, 2012
• 年：2012
• 卷：12
• 期：11
• 页码：5890-5896
• 全文大小：456K
• 年卷期：v.12,no.11(November 14, 2012)
• ISSN：1530-6992

文摘

We report a simple, controlled doping method for achieving n-type, intrinsic, and p-type lead sulfide (PbS) nanowires (NWs) grown by chemical vapor deposition without introducing any impurities. A wide range of carrier concentrations is realized by adjusting the ratio between the Pb and S precursors. The field effect electron mobility of n-type PbS NWs is up to 660 cm²/(V s) at room temperature, in agreement with a long minority carrier diffusion length measured by scanning photocurrent microscopy (SPCM). Interestingly, we have observed a strong dependence of minority carrier diffusion length on gate voltage, which can be understood by considering a carrier concentration dependent recombination lifetime. The demonstrated ambipolar doping of high quality PbS NWs opens up exciting avenues for their applications in photodetectors and photovoltaics.

Keywords:

Nanowires; lead sulfide; doping; field effect transistors; scanning photocurrent microscopy; carrier diffusion length