Highly photoresponsive VO2(M1) thin films synthesized by DC reactive sputtering

Abstract

We report synthesis, characterization and IR photoresponse properties of 150 ± 10 nm thick high quality VO2(M1) thin films synthesized by DC reactive sputtering. Phase formation was confirmed by X-ray diffraction and Raman spectroscopic measurements. Morphology and microstructure were analysed by atomic force microscope, scanning electron microscope and transmission electron microscope which revealed polycrystalline nature of nanosized films with root mean square (rms) roughness value of 8 ± 0.7 nm. Electrical measurements revealed 1st order transition of thin films with a change in resistance of more than two orders of magnitude and temperature coefficient of resistance, TCR of − 1.24% K−1 at 30 °C. The fabricated VO2(M1) IR photodetector exhibited excellent reproducible photoresponse properties when subjected to a 1064 nm laser under 250 mW cm−2 power density with a bias voltage of 5 V at the ambient conditions of temperature and pressure. The sensitivity, responsivity, external quantum efficiency and specific detectivity were observed to be 1775%, 40.09 mA W−1, 4.67% and 7.07 × 1011 Jones, respectively.