Improved High‐Purity Arc‐Furnace Silicon for Solar Cells

Abstract

Single-crystal silicon solar cells having efficiencies within 1% of those prepared in semiconductor-grade silicon have been fabricated in twice-recrystallized, high purity metallurgical silicon.

Processes for Production of Solar‐Grade Silicon Using Hydrogen Reduction and/or Thermal Decomposition

“…[34,35] In this case, MG-Si is prepared from high-purity SiO 2 and highpurity carbon to reduce the amount of impurities, and the impurities in MG-Si are subsequently removed by using acid leaching. [36][37][38][39][40] This type of leaching process is still under investigation. [41][42][43] In the literature, the maximum reported purity has been 4N, attained by employing only the acid leaching treatment.…”

Efficiency Improvement of Crystalline Solar Cells: Final Subcontract Report, 1 January 2002 - 30 September 2006

“…The typical impurity level in MG-Si manufactured through this process is 98-99% and even 95% because the raw materials used in this process contain high impurity levels. It is possible to obtain much higher degree of purity of silicon at a reasonable cost by using either naturally clean, or purified by leaching silica or quartz and carbon black or pelletized activated carbon with higher than average purity in specially-designed arc furnaces with purified electrodes [62,[67][68][69][70][71][72][73][74].…”

Solar Grade Silicon from Agricultural By-products

“…[1][2][3][4][5][6][7] The motivation for using RH and in our work, rice hull ash (RHA), comes from the fact that all plants (to some extent) extract SiO 2 from the soil. In particular, grasses including rice, wheat, oats and barley have high concentrations of SiO 2 in their hulls, husks or stalks.…”