Table 1 Measured properties of SiNWs with varying porosity and doping levels investigated in this study.

From: High thermoelectric figure of merit of porous Si nanowires from 300 to 700 K

Starting wafer (p, σ, κ)

P (~9 × 1014 cm−3, 10 S/m, 145 W/m-K)a

P+ (~8 × 1016 cm−3, ~103 S/m, 134 W/m-K)a

P++ (~1 × 1019 cm−3, 105 S/m, 113 W/m-K)a

H2O2 (M)

0.22

0.22

0.33

0.44

0.22

Porosity (%)

9

46

60

67

61

Post-doping

No

Yes

No

Yes

Yes

Yes

Yes

Yes

No

Final doping level (p, ×1018 cm−3)

1.6E-5c

2.1

3.9E-3c

4.7

23

220

12.7

34

4.8

Si crystallite size (nm)

4.7

4.7

3.9

3.9

3.9

3.9

3.8

3.8

3.8

κ (W/m-K)b

9.32

9.13

5.43

4.41

4.08

4.85

3.19

2.18

2.56

σ (S/m)b

0.03

3258

1.05

2886

11,950

115,101

32.3

0.51

3.63

S (μV/K)b

 

445.1

 

430.9

381.7

206.2

419.3

  

ZT (300 K)

 

0.021

 

0.037

0.13

0.31

0.00053

  

ZT (700 K)

 

0.098

 

0.16

0.35

0.71

0.0076

  
  1. aσ and κ are room temperature results adapted from ref. 36 for bulk Si with close doping concentrations.
  2. bκ, σ, and S of the porous SiNWs shown in this table are measured room temperature results.
  3. cThe doping concentration of these samples is obtained by fitting the electrical conductivity model37 as SIMS is not able to measure boron concentrations lower than 1016 cm−3.
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