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

M R Balboul,A Sharaf,I S Yahia,A Abdel-Galil

doi:10.1155/2016/3183909

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.

Highlights

Cadmium sulfide (CdS), with typical II–VI semiconductor properties, is a basic object of nanotechnology where the modification of their electrical and optical properties provides nanomaterials with unique application in the fields of electronics and optoelectronic devices [1,2,3]
The electrical properties of II–VI semiconductor compounds are drastically affected by impurities and native defects, which can be controlled by several techniques such as gamma irradiation [4,5,6,7]
The optimization of CdS films characteristics has created a need for a better understanding of its electrical properties, which have been investigated intensively, while few studies on gamma irradiation have been available in the literature [8, 14, 15]

Summary

Introduction

Cadmium sulfide (CdS), with typical II–VI semiconductor properties, is a basic object of nanotechnology where the modification of their electrical and optical properties provides nanomaterials with unique application in the fields of electronics and optoelectronic devices [1,2,3]. The electrical properties of II–VI semiconductor compounds are drastically affected by impurities and native defects, which can be controlled by several techniques such as gamma irradiation [4,5,6,7]. The irradiation creates a wide variety of defect states in the material system by ionization or excitation processes which form new electronic configuration coordinates that cause a change in electrical response of the material and its physical properties [8, 9]. These changes are strongly dependent on the exposure dose. The novelty of this study is to modify the electrical properties of CdS thin films by exposing them to specific doses of gamma irradiation, which makes change in dc electrical conductivity, carrier concentration, Hall mobility, Hall coefficient, and flat band potential

Experimental

Results and Discussion

NDeεε0A2

Conclusion