Characterizing the influence of various RF powers of Sputtering system on the electrical properties of Ni-DLC semiconductor thin films

Abstract Nickel nanoparticles doped amorphous diamond-like carbon were sputtered by the RF-PECVD technique in different applied powers. Subsequently, the Effect of increasing RF power on the surface texture and conduction mechanism was analyzed and reported. EDAX spectroscopy implies the growth of nickel and carbon content. Scanning Electron Microscopy (SEM) shows that the nanoparticles of Ni-DLC within the increasing applied power were more agglomerated and homogenized. Electrical measurements were done to launch a full investigation into the charge transport mechanism of films and determine the type of transportation mechanism in the temperature range from 123 K to 573 K. Based on the electrical properties, using the Arrhenius model in the high-temperature ranges from 573 K to ~ 380 K, S3 samples have a minimum value of inter-band activation energy about of 6 meV, indicating more conduction due to more nickel content compared to the other samples which can be a reason based on an argument that the nickel content could be controlled by regulating different RF applying deposition power, while in low-temperature range the conduction mechanism follows a phonon-assistant hopping. This research revealed that in Ni:a-C:H semiconductor thin films the adopted mechanism in the low-temperature region (VRH conduction mechanism) is different from the high-temperature one (band-to-band conduction) and changes from the VRH to the band-to-band conduction with rising temperature. Furthermore, by increasing the nickel content, the hopping distance was reduced in the samples.