Hydrogenation maneuvered In 2 O 3 /InN core-shell nanorod and its consequences on NO 2 gas sensing behavior.

In this work, the first time we made InN/In2O3core-shell heterostructure by hydrogen plasma treatment. InN nanorods (NRs) were grown by using plasma-assisted molecular beam epitaxy and hydrogen plasma treatment was performed by using the reactive ion etching system at room temperature. From X-ray photoemission spectroscopy studies, it was noticed that the bonding partner of In changes from N to O and N 1s completely disappeared in hydrogenated InN NRs. Further, high-resolution transmission electron microscopy revealed that the formation of InN/In2O3core-shell NRs by hydrogenation plasma treatment. The resistance of pristine InN NRs was decreased in NO2ambient. Interestingly, the resistance of the InN/In2O3core-shell was increased while introducing NO2gas. InN NRs surface exhibits downward band bending due to the electron accumulation, in NO2ambient, the surface band bending was decreased due to the increase in bulk conduction channel. This reversed gas sensing behavior in InN/In2O3core-shell NRs was attributed to the increase in depletion layer while reducing conduction channel width by absorption of NO2. The InN/In2O3core-shell NRs exhibited a response of 22.43 % at 50(o)C, which was 5.11 times higher than that of pristine InN NRs.