Synthesis and Characterization of VO 2 on III Nitride Thin Films Using Low Pressure Chemical Vapor Deposition for Sensing Applications

The sharp transition in electrical and structural properties of Vanadium dioxide during the Metal-Insulator Transition (MIT) is highly attractive for various electronic, optoelectronic and sensing applications. In this work, we have studied Chemical Vapor Deposition based synthesis of VO 2 on Gallium Nitride (GaN) thin films and compared them with those synthesized on Silicon and Sapphire. Thin film vanadium metal (70 nm) was deposited on the various substrates, followed by oxidation under controlled conditions to obtain VO 2 films. The effect of deposition time, oxygen flow rate, substrate temperature, radiative cooling time and furnace pressure systematically studied to obtain the best quality films. Synthesis was carried out on large area vanadium deposited samples as well as on microscale vanadium patterned samples. The as-grown VO 2 films were characterized using AFM and XRD technique to determine their structural and crystalline qualities. VO 2 films synthesized under optimal CVD growth conditions on were successfully utilized for in GaN MEMS devices for highly sensitive deflection transduction.