Tungsten oxide nonvolatile memory devices using photothermal in-situ oxidation method

•The Au/WOx/W memory devices were fabricated through a photothermal oxidation method.•The photothermal oxidation method can monitor the oxidation process in real time.•The ON/OFF ratio of devices was as large as ~ 102 at a 2 V reading voltage.•Memory mechanisms for device are described using fitted the I–V curves. The tungsten oxide nonvolatile memory devices were fabricated using the photothermal in-situ oxidation method. The photothermal in-situ oxidation method can monitor the oxidation process in real time. Raman spectra revealed that tungsten oxides were formed by thermal oxidation. The ON/OFF ratio of the current bistability for the device was as large as ~ 102 at a 2 V reading voltage, and the cycling endurance of the ON/OFF switching for the devices was stable without noticeable degradation. Memory mechanisms for device are described using fitted the I–V curves.