Lighttrapping improvement of limited-quality silicon wafers for silicon heterojunction solar cell applications

Abstract

Laser-based surface texturing treatments

have been investigated as a promising option for innovative

low-cost concepts to improve the light absorption of silicon

heterojunction solar cells manufactured from

unconventional silicon wafers. A great advantage of using a

laser as a processing tool is its high precision, which lead to

selected and well-controlled morphologies. This is a

particularly interesting feature for multicrystalline silicon

wafers, where the large number of grain boundaries makes

it difficult to obtain high light-trapping morphologies by

other methods. The investigations described in this work

include testing different patterns on the wafer surface in

order to define the best morphology to improve the light

absorption. A significant decrease in reflectance (R<9%)

has been achieved by direct-laser texturization and has been

compared with acid-chemical etching with average

reflectance above 20%. This result suggests the enormous

potential of direct laser texturization for this type of wafers,

without chemical residues and its easy incorporation to the

manufacturing of low-cost silicon heterojunction solar cells.