Current localization in heterostructures of multijunction solar cells: Causes for arising and diagnostics potential

摘要

A technique to reveal any local inhomogeneities formed heterointerfaces in multi-junction (MJ) solar cell (SC) structures is proposed. The methodology is based on the nature of two temperature-differentiated processes initiated in the multilayer structures at direct current passing: general cooling with the manifestation of structural areas with a reduced potential barrier for charge carriers and the inevitable concentration of the carrier flux in such areas with the local heating of the structure accompanying this process because of increase in charge carriers density. The methodology is based on the nature of two temperature-differentially directed processes initiated in the multilayer structure of solar cells: general cooling with the manifestation of structural regions with a reduced potential barrier for photogenerated charge carriers and inevitable concentration of the carrier flux in such areas with the local heating of the structure accompanying this process. The triggered avalanche-like process leads to a current pinching with the corresponding localization of EL light emission. Investigation of the EL emission profile at localization points with simultaneous recording the MJ SC voltage values allows making the relative estimations of barrier height in the selected regions of the structure with subsequent absolute determination of the values for the "potential" and the "resistive" inhomogeneities.