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Experiments involving correlations between CdTe solar cell fabrication history and intrinsic device stability | IEEE Conference Publication | IEEE Xplore

Experiments involving correlations between CdTe solar cell fabrication history and intrinsic device stability


Abstract:

An orthogonal full-factorial design was used to study the effect of CdS and CdTe layer thickness, oxygen ambient during vapor CdCl/sub 2/ (VCC) and the use of nitric-phos...Show More

Abstract:

An orthogonal full-factorial design was used to study the effect of CdS and CdTe layer thickness, oxygen ambient during vapor CdCl/sub 2/ (VCC) and the use of nitric-phosphoric (NP) acid as a pre-contact etch on the initial and stressed performance of CdS/CdTe small-area devices. The best initial device efficiency (using thinner CdS, thicker CdTe, no oxygen during VCC, and NP etch) also showed poor stability. Increasing the CdS thickness significantly improved stability with only a slight decrease in resulting initial performance. All devices used a thin margin of CdTe around the perimeter of the backcontact that was shown to significantly reduce catastrophic degradation and improve overall test statistics. The latter degradation is modeled by the formation of a weak-diode/low shunt resistance localized near the edge of finished devices. This shunting is believed to occur through the CdS/CdTe interface, rather than along the device edge, and is exacerbated by thinner CdS films and fabrication defects resulting in direct metal-CdTe contact.
Date of Conference: 03-07 January 2005
Date Added to IEEE Xplore: 08 August 2005
Print ISBN:0-7803-8707-4
Print ISSN: 0160-8371
Conference Location: Lake Buena Vista, FL, USA

Introduction

The success of photovoltaics as a viable source of renewable energy will be achieved by balancing performance, cost, and reliability. To date, much of the current knowledge regarding polycrystalline thin film devices has focused on optimizing initial performance. In this work, we present empirical optimization experiments specifically designed to study the balance between performance and stability.

References

References is not available for this document.