title: Modulation of thermoelectric power factor via radial dopant inhomogeneity in B-doped Si nanowires.
abstract: We demonstrate a modulation of thermoelectric power factor via a radial dopant inhomogeneity in B-doped Si nanowires. These nanowires grown via vapor-liquid-solid (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 δ-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.
authors.affiliation: Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Fuwei
authors.initials: F
authors.lastname: Zhuge
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yanagida
authors.forename: Naoki
authors.initials: N
authors.lastname: Fukata
authors.forename: Ken
authors.initials: K
authors.lastname: Uchida
authors.forename: Masaki
authors.initials: M
authors.lastname: Kanai
authors.forename: Kazuki
authors.initials: K
authors.lastname: Nagashima
authors.forename: Gang
authors.initials: G
authors.lastname: Meng
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.forename: Sakon
authors.initials: S
authors.lastname: Rahong
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Li
authors.forename: Tomoji
authors.initials: T
authors.lastname: Kawai