Continuous Monitoring of VHF-GD Deposited p-i-n Solar Cells during Uniform Degradation Till Saturation

Abstract

This paper addresses the prioritary issue of the Staebler -Wronsky effect (SWE) in p-i-n Solar cells. In previous publications it was shown, that VHF-GD yields individual layers and solar cells with results comparable to 13.56 MHz GD. In this paper we present the first results of the degradation behaviour of VHF-GD solar cells. To this end, we applied a fast degradation technique wherein the SWE on the solar cell parameters (V_oc,I_sc, FF, η) was measured until saturation occured. In order to check the uniformity we used LBIC, (Light Beam Induced Current) Thermography and CCD (Charge Coupeled Device) beam shaping, thus making sure, that the solar cell parameters are isotropic values coming from the degraded volume. By continuous monitoring it is possible to observe the saturation behaviour of the cell parameters and the validity of the power-law. In situ monitoring permits to find a relation between the saturation values and the intensity which is applied for light soaking.