Modulation of Thermoelectric Power Factor via Radial Dopant Inhomogeneity in B-Doped Si Nanowires

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• 作者：Fuwei Zhuge ; Takeshi Yanagida ; Naoki Fukata ; Ken Uchida ; Masaki Kanai ; Kazuki Nagashima ; Gang Meng ; Yong He ; Sakon Rahong ; Xiaomin Li ; Tomoji Kawai
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：October 8, 2014
• 年：2014
• 卷：136
• 期：40
• 页码：14100-14106
• 全文大小：411K
• ISSN：1520-5126

文摘

We demonstrate a modulation of thermoelectric power factor via a radial dopant inhomogeneity in B-doped Si nanowires. These nanowires grown via vapor鈥搇iquid鈥搒olid (VLS) method were naturally composed of a heavily doped outer shell layer and a lightly doped inner core. The thermopower measurements for a single nanowire demonstrated that the power factor values were higher than those of homogeneously B-doped Si nanowires. The field effect measurements revealed the enhancement of hole mobility for these VLS grown B-doped Si nanowires due to the modulation doping effect. This mobility enhancement increases overall electrical conductivity of nanowires without decreasing the Seebeck coefficient value, resulting in the increase of thermoelectric power factor. In addition, we found that tailoring the surface dopant distribution by introducing surface 未-doping can further increase the power factor value. Thus, intentionally tailoring radial dopant inhomogeneity promises a way to modulate the thermoelectric power factor of semiconductor nanowires.