1. No category

(1)
Fabrication and measurement of thermoelectric properties
using bismuth nano-wire element
(Hiroya Yamamoto)
(Fumiaki Tsunemi)
(Yasuhiro Hasegawa)
(Tokyo Univ. ISSP)
(Ibaraki Univ.)
(NIMS)
(SAITEC)
Development of clean new energy to turn into fossil fuel is demanded from problems
such as the global warming. Thermoelectric generation is one of ways to generate
electricity, but it is not in use for a general generation method because generation
efficiency is low as compared with solar energy generation .
Low-dimensional configurations such as superlattices and nanowires have been
theoretically expected to enhance the performance of thermoelectric materials. Our
group have fabricated new bismuth nanowire sample using a quartz template, which
has several hundred nano-scale diameter and over 1mm length.
It is predicted that a change of the Fermi energy happens when the diameter of
nanowire reduces. We observed Shubnikov-de Haas oscillations of single-quartz
bismuth nanowire in order to measure this change. In addition, We constructed
thermal conductivity measurement using steady state method preventing heat leak.
z
12


E
1 1

i


Ei Ei 
 ωc,i  n    sg i μ B B i  A, B, C 


Eg 
2 2


y

L
x d
z
1 1

E0  Eh  ωc,h  n    sg h μB B
2 2

hole
E0  38.5 meV
EF  27.6 meV
(A)
(B)
T holes
E g  15.3 meV
electron
y
M H  hˆ  M  hˆ
hˆ
EF
L electrons
(C)
  E 

N e,i EF   2 2 eB   EF 1  F   Ei n, s  i  A, B, C 
 E 
n,s 
2π 
g 

 
2mh,H
12
N h EF   2 2 eB  E0  EF   Eh n, s 
n,s
2π 
2mi.H

B
n0
n 1
n2
n3
n4
B // Trigonal

x

F. Y. Yang et al., PRB (2000)

ΔT2

2
Z
 
ΔT1
I+
IVV+
1 l
  Q

T S
（S:断面積、l:長さ）
Qh  Vh  I h
Cernox
温度センサー



I-
I+