The influence of high-energy alpha-particle irradiation on the spectral and defect properties of a Si photovoltaic detector

In this study the influence of 5.4 MeV alpha-particle irradiation on the pe rformance of a Si photovoltaic detector, designed for system positioning, w as investigated. The responsivity of the detector at 900 nm was reduced fro m 0.59 A W-1 for the unirradiated detector to 0.23 A W-1 for a detector whi ch was irradiated with an alpha-particle fluence of 4.34 x 10(11) cm(-2). U sing deep-level transient spectroscopy (DLTS) and current-voltage measureme nts (I-V) the influence of alpha-particle irradiation on the defect and ele ctrical properties of the detectors was monitored. The electro-optical char acterization was performed using an optical characterisation test station. From this preliminary investigation it would seem that alpha-particle irrad iation definitely degrades the spectral response of a system-positioning ph otovoltaic detector. This irradiation introduces electron and hole defects in the bandgap, which have a detrimental effect on the electrical propertie s (reverse leakage current, dynamic resistance and ideality factor) of the junction.