Effect of radio frequency power on composition, structure and optical properties of MoSex thin films

MoSex films were prepared by radio frequency (RF) magnetron sputtering under various RF powers in the range of 40–130 W. Effects of RF power on composition, structure and optical properties of MoSex films were investigated. Results show that the chemical bonding, binding energy, structure, and optical properties of MoSex films depend greatly on RF power. When the RF power varies from 40 to 70 W, the bonding atomic ratio of Se/Mo in MoSex films increase and Mo 3d5/2 and Se 3d5/2 peaks shift towards lower binding energies. With further increase in the RF power from 70 to 130 W, the bonding atomic ratio of Se/Mo in MoSex films decreases and Mo 3d5/2 and Se 3d5/2 peaks move to higher binding energies. Structures of MoSex films are amorphous with the RF power ≤70 W, whereas structures of MoSex films exhibit nanostructure with the RF power >70 W. Moreover, MoSex films deposited at 70 W have larger refractive index, lower extinction coefficient, and higher band gap than those deposited at other RF power.