Post-Grant Reports

Title

Impact of a Back Contact Barrier on Capacitive Measurements of Solar Cells

Document Type

Report

Publication Date

3-9-2014

Disciplines

Engineering Physics | Physics

Abstract

Recent solar cell technology, in striving for lowest cost, results in materials with many imperfections. Capacitance measurements are a common, nondestructive method to identify defects which compromise the device performance. These techniques assume that the device includes a single blocking contact, or “top” contact; however, these imperfect devices often also have a non-ideal “back” contact. In this project, the ideal and non-ideal contact response was modeled using SCAPS software. Simple circuits, using back-to-back diodes in series, confirmed the model predictions for our experimental setup. Our subsequent measurements of a Cu(In,Ga)Se2 solar cell could then be clearly interpreted as demonstrating a non-ideal contact. This work lays the foundation for a study of the contact properties, the barrier height, relationship to bulk and interface defects in the film, and the dependence on sample preparation and stoichiometry. This work addresses a topic of significant debate in the Cu(In,Ga)Se2 solar cell research community. Results were presented at the 2013 Murdock Trust conference in Vancouver, WA and at the 2014 March Meeting of the American Physical Society in Denver, CO.

Comments

This research was conducted as part of a Linfield College Student-Faculty Collaborative Research Grant in 2013-2014, funded by the Office of Academic Affairs.

Student collaborators were Justin Davis and Addison Wisthoff.

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