Abstract: A GaN power semiconductor device integrated with a self-feedback gate control structure comprises a substrate, a buffer layer, a channel layer and a barrier layer. A gate control area is formed by a first metal source electrode, a first P-type GaN cap layer, a first metal gate electrode, a first metal drain electrode, a second P-type GaN cap layer and a second metal gate electrode. An active working area is formed by the first metal source electrode, a third P-type GaN cap layer, a third metal gate electrode, a second metal drain electrode, the second P-type GaN cap layer and a second metal source electrode. The overall gate leaking current of the device is regulated by the gate control area, the integration level is high, the parasitic effect is small, and the charge-storage effect can be effectively relieved, thus improving the threshold stability of the device.

Abstract: An electrode material comprising 0.5-50 wt % functionalized graphene material and a capacitor comprising the electrode material are provided. A method for preparing the functionalized graphene material is also provided. The method comprises the step of chemically reducing the soluble graphene material and the step of physically reducing the chemically reduced graphene material.