Electrical Response of CdS Thin Film and CdS/Si Heterojunction to Gamma Radiation

Abstract

Gamma irradiation method has been used to change the electrical properties of CdS thin film. A specific dose ofγ-irradiation increases the activation energy of CdS thin film. In addition,γ-irradiation was used to change the sign of Hall coefficient,RH, of CdS thin film from negative to positive irrespective of temperature. The Hall mobility mechanism shows noticeable change afterγ-irradiation from decreasing to increasing with raising the temperature. In depth, analysis was done using capacitance-voltage measurement in order to realize the modification in the CdS/Si junction band gap afterγ-irradiation. Several parameters were also studied such as charge carrier concentration,ND, and flat band potential,Vfb. Theγ-irradiation was found to increase the concentration of the deep traps within the band gap of the CdS/Si heterojunction.