After gold deposition, the devices were annealed at 2500 C for ~ 2 h in forming gas. This was subsequently followed by high vacuum annealing for 24 h at 1200 C. Atomic force microscopy (AFM) imaging was performed using the Asylum Research MFP-3D AFM. Electrical characterization was performed by using a combination of sourcemeter (Keithley 2612 A), Lock-In amplifier (Signal Recovery 7265) and resistance bridges (Lakeshore 370) coupled to a Physical Property Measurement System. The Raman spectra were measured in a backscattering geometry using a 488 nm laser excitation wave-length. Sub-Angström aberration corrected transmission electron microscopy was performed by using a JEM-ARM200cF microscope. EDS was performed through field- emission scanning electron microscopy (Zeiss 1540 XB).