Effect of Gamma Rays on Schottky Diodes of Au/n-Si type

Abstract

This work includes studying the effect of gamma radiation on the electrical properties of Au/n-Si Schottky diode by depositing a thin layer of gold on (111) n–Si by thermal evaporation under vacuum. The device was radiated for variable periods as (1-60) days. From (I –V) characteristics in the dark, the results show a reduction in the forward bias current value, and there was a small increase in the reverse bias current. Also, the forward current of the devices radiated before depositing the gold was larger than the forward current of those radiated after depositing the gold. For non- radiated device, the values of ideality factor and barrier height potential were equal to
1.05 and 0.81eV respectively, while for devices radiated before and after depositing the gold , the values ranged between (1.05- 1.17) for ideality factor and (0.81–0.858)eV for barrier height potential. This concludes that the current mechanism for all non-radiated and radiated devices is thermonic emission. For non-radiated devices the values of the short circuit current and the open circuit voltage were equal to 0.489 mA and 280.4 mV, respectively, while for devices radiated for periods between (1-60) days before and after gold deposition on top surface, the measurements show that the value of short circuit current and open circuit voltage increased to the maximum value within the irradiated devices, while for one day (80mA, 300mV), respectively , for which the efficiency is equal to 19.32%. The values of (V_OC, IS_C) reduced sharply with increasing radiation periods. T he short circuit current and open circuit voltage values in radiated devices before gold deposition are bigger than those of radiated devices after gold deposition on the top surface. From (C – V)
measurements, the results show a reduction in the capacity value with increasing radiation periods for all devices before and after gold deposition.