Studies on backside Al-contact formation in Si solar cells : fundamental mechanisms : preprint / B. Sopori [and others].

Format:

Book

Government document

Contributor:

Sopori, Bhushan Lal

National Renewable Energy Laboratory (U.S.)

Series:

Conference paper (National Renewable Energy Laboratory (U.S.)) ; NREL/CP-520-45001.

Conference paper ; NREL/CP-520-45001

Language:

English

Subjects (All):

Photovoltaic cells--Research.

Photovoltaic cells.

Solar cells--Design and construction.

Solar cells.

Physical Description:

1 online resource (6 pages)

Place of Publication:

[Golden, Colo.] : National Renewable Energy Laboratory, [2009]

Summary:

We have studied mechanisms of back-contact formation in screen-printed Si solar cells by a fire-through process. An optimum firing temperature profile leads to the formation of a P-Si/P+-Si/ Si-Al eutectic/agglomerated Al at the back contact of a Si solar cell. Variations in the interface properties were found to arise from Al-Si melt instabilities. Experiments were performed to study melt formation. We show that this process is strongly controlled by diffusion of Si into Al. During the ramp-up, a melt is initiated at the Si-Al interface, which subsequently expands into Al and Si. During the ramp-down, the melt freezes, which causes the doped region to grow epitaxially on Si, followed by solidification of the Si-Al eutectic. Any agglomerated (or sintered) Al particles are dispersed with Si. Implications on the performance of the cell are described.

Notes:

Title from title screen (viewed February 27, 2009).

"Presented at the Materials Research Society (MRS), Fall Meeting 2008, Boston, Massachusetts, December 1-5, 2008."

"February 2009."

OCLC:

311081407