Study of Low Voltage Prebreakdown Sites in Multicrystalline Si Based Cells by the LBIC, EL, and EDS Methods

V I Orlov,E P Magomedbekov,E B Yakimov,A B Danilin

doi:10.1155/2017/1946490

Abstract

Breakdown sites in multicrystalline Si solar cells have been studied by reverse-bias electroluminescence, electron beam induced current (EBIC) and laser beam induced current (LBIC), and Energy Dispersive X-Ray Spectroscopy methods. In the breakdown sites revealed by EL at small reverse bias (~5 V), the enhanced aluminum and oxygen concentration is revealed. Such breakdowns can be located inside the depletion region because they are not revealed by the EBIC or LBIC methods. Breakdowns revealed by EL at larger bias correlate well with extended defects in the EBIC and LBIC images.

Highlights

Solar cells made from Si regularly suffer from shunts, which are internal short circuits degrading the parameters of the cells and often even preventing their applicability
A large area EL image of solar cell obtained at reverse bias of 10 V is shown in Figure 1
Typical breakdown sites revealed at small bias are shown in Figures 2(b) and 2(c) as two bright spots with brightness increasing with reverse bias

Summary

Introduction

Solar cells made from Si regularly suffer from shunts, which are internal short circuits degrading the parameters of the cells and often even preventing their applicability (see [1,2,3,4,5,6] and the references therein). Among various types of shunts, those associated with local breakdown of solar cells under reverse bias can be mentioned [5,6,7,8,9]. The breakdown sites in multicrystalline Si based solar cells are revealed by the reverse-bias EL.

Results

Conclusion