RF magnetron sputtered deposited metal-doped diamond like carbon thin films: structural, morphological, mechanical, and optical properties

Abstract

The present study investigates the surface, structural, mechanical and optical properties of (0, 1%, 2%, 3%, 4%, 5%) palladium doped diamond like carbon (Pd;DLC) thin films prepared by using r. f. magnetron sputtering technique. The structural, mechanical, surface, and optical properties were measured by Energy Dispersive X-rays (EDX), Raman spectroscopy, Vickers Hardness Measurement (VHM), atomic force microscopy (AFM), and Spectroscopy Ellipsometry, respectively. EDX results clearly indicated the presence of palladium metal into DLC matrix. Raman spectroscopy results reveal that all Raman spectra consist of two main peaks as D-band (1355.7 to 1359.3) and G-band (1558.9 to 1577.9). Additionally, ID/IG ratio increases monotonically from 0.391 to 0.504 with increasing palladium concentration. With increasing doping concentration, AFM shows a modest increase in roughness of Pd-DLC thin films. The decline in the hardness of Pd-DLC films from 9.38 Gpa for 1% to 8.90 Gpa for 5% were observed by using Vickers Hardness Measurement (VHM). Spectroscopy ellipsometry showed that Eg reduced from 2.11 to 1.68 eV by adding the palladium concentration in Pd-DLC film. The decrease in the optical bandgap energy over the wide range is due to enrichment of sp2 contents than undoped film. The results reveal that incorporation of palladium produced prominent change in different properties of DLC film by increasing sp2 content. At 5% doping 1.68 eV band gap is achieved which is very ideal for solar cells fabrication. Therefore, this film is very good for solar cells and LEDs fabrications.