Numerical simulation of the type inversion in n+-p-p+ Si solar cells, used for space applications, under 1 MeV electron irradiation

Abstract

Solar cells, used for space applications, are exposed to energetic particles such as protons and electrons. The energetic particles create defects in the active region of the solar cell and the latter performance can be severely degraded. One of the phenomenons observed in Silicon solar cells exposed to 1 MeV electron irradiation is type inversion of its active region. This behaviour is numerically simulated using the SCAPS software. The current-voltage characteristics of a Si n+-p-p+ structure are calculated under AM0 for different fluences of 1MeV electrons. It was found that, amongst the many defects created, only one of them is responsible for type inversion. It is a minority trap that is an electron trap in the p-type base of the n+-p-p+ solar cell.