Table 1

Impurity concentrations (ppm) before (SPw) and after thermal annealing
SPw (ref.) 700°C 800°C 900°C
Fe 5,100 20.77 10.54 0.41
Al 2,200 100.15 20.17 2.13
Ti 421 23.9 2.93 2.83
As 2 0.7 <0.05 <0.05
P 16 11 10 10
B 0.7 <0.05 <0.05 <0.05
Ni 5.6 3.1 1.4 0.17
Cu 5.5 1.8 1.5 0.14
Ca 98.1 10.21 9.85 9.1
Na 38 15.09 8.84 1.44
Mn 793 297 139 13.9
Mg 55 83 71 7
K 20 3.7 2.4 2.3
Cr 230 107 13 1.7
Co 7 6 6 6
Total (%) 0.9 0.07 0.03 0.01
Purity (%) 99.10081 99.93166 99.97034 99.99489

Annealing temperatures are 700°C, 800°C, and 900°C of silicon powder with a thin porous layer.

Khalifa et al.

Khalifa et al. Nanoscale Research Letters 2012 7:444   doi:10.1186/1556-276X-7-444

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