Numerical Simulations for In‐Depth Analysis of Transmission Line Method Measurements for Photovoltaic Applications—The Influence of the p–n Junction. Issue 4 (7th November 2019)

• Record Type: Journal Article
• Authors: Urban, Tobias; Heitmann, Johannes; Müller, Matthias
• Other Names: Hiller Daniel guestEditor.; Duffy Ray guestEditor.; Strehle Steffen guestEditor.; Stradins Paul guestEditor.
• Is Part Of: Physica status solidi. Volume 217:Issue 4(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-07
• Subjects: contact resistivity -- measurement uncertainty -- solar cells -- transmission line method; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201900600
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : For optimization of solar cell perfomance, the knowledge of the specific contact resistivity between grid finger and emitter is an important component. The contact resistivity is typically characterized by transmission line method (TLM) measurement directly on samples made from complete fabricated solar cells. Large contact spacing on solar cells leads to high measured resistances and thus high voltage drops along the emitter, measuring between several finger distances. This, in turn, imposes a strong load on the p–n junction and can lead to a parasitic current flow over the wafer base itself. The influence of this current flow on the TLM measurement evaluation for typical solar cell parameters is investigated. The 2D simulation of TLM measurements is used to derive handling instructions to improve the contact resistivity measurements. For typical solar cell TLM stripes with emitter sheet resistances of about 150 Ω sq −1 and a reverse p–n junction characteristic similar to r shunt in the range of 10 kΩ cm 2, an influence of about 10% or higher ρ c evaluation uncertainty is expected. Abstract : An investigation on the evaluation quality for contact resistivity measurements is conducted by simulated transmission line method (TLM) measurement, depending on the vertical isolation between emitter and wafer base with solar cell typical configurations. It is shown that already typical solar cell TLM configurations can cause deviations of up to 10% and more. Using the simulations in this study, measuring instructions are derived to reduce measurement evaluation uncertainty.