(a) Structure of the PERC solar cell. The surface texturing is not shown. (b) Cross-sectional diagram of the alloyed junction structure of screen printed Al fingers at the rear of the PERC cell [see rectangle (a), inverted], not in scale. d2: Al finger width. d1: dielectric barrier opening width . The layers formed after the alloying are: (a) Al matrix, (b) Al–Si alloy, and (c) BSF.
Total contact resistance R not increasing for broader openings (-axis at the right), and contact resistivity of a Al finger width, d2, alloyed on four different dielectric barrier opening widths, d1. The error bars represent the variation in for different firing conditions (-axis at the left).
Cross-sectional SEM micrographs. The BSF (up to deep) is marked and formed few micrometers underneath the dielectric barrier. (a), (b), and (c) show a Al finger width printed on , , and dielectric barrier openings, respectively. (d) view of (c) after complete removal of the Al–Si alloy and Al matrix, using hydrofluoric acid (HF) and hydrochloric acid (HCl).
(a) Cross-sectional SEM micrographs after HF, HCl etching of the Al matrix, and Al–Si alloy for a sample printed without alignment. (b) Schematic cross-section of the experiments done for this article, not in scale . Top: Al–Si alloy homogeneous formed for narrow dielectric barrier openings; middle: two alloys formed at the opening edges for wider contact areas and the same Al mass; and bottom: the Al–Si alloy depends on the ratio: Al finger width to dielectric barrier opening width.
Article metrics loading...
Full text loading...