“…Notably, W/WO 2 and WO 3-x /Au exhibit nonrectifying behavior, signifying Ohmic contacts. [68] This observation is consistent with the metallic characteristics of WO 2 , which results in a linearly adjustable resistance upon contact with W. [69] Furthermore, as N-type semiconductors, both WO 2 and WO 3-x have work functions higher than metals(W/Au), indicating that the surface electron concentration of semiconductors is higher than that inside the material, resulting in the formation of a reverse barrier layer. Therefore, under forward bias, highconcentration electrons easily flow towards the metal, and under reverse bias, the applied electric field is opposite to the built-in electric field, allowing electrons in the metal to readily cross the barrier and enter the semiconductor, thus forming Ohmic contact.…”