Influence of high dose gamma irradiation on electrical characteristics of Si photo detectors

The radiation response of Si photo detectors has been studied through Current voltage (I-V) and Capacitance Voltage (C-V) measurements for accumulated high doses of Co-60 gamma rays in the wide range of 1 Mrad to 100 Mrad. The key electrical parameters such as ideality factor (n), series resistance (RS) and reverse leakage current (IR) has been extracted from I-V characteristics. The acceptor concentration (NA) was extracted from C-V characteristics. The detectors exhibited degradation in the values of electrical parameters up to 60 Mrad, further at higher doses improvement in their values is noticed. The lattice defects introduced by gamma rays may have significantly contributed to the deterioration of device parameters at initial doses, whereas the partial recovery at higher does is attributed to annealing effect of gamma rays due to its electronic energy loss (Se) component