The present description relates to n-channel gallium nitride transistors which include a recessed gate electrode, wherein the polarization layer between the gate electrode and the gallium nitride layer is less than about 1 nm. In additional embodiments, the n-channel gallium nitride transistors may have an asymmetric configuration, wherein a gate-to drain length is greater than a gate-to-source length. In further embodiment, the n-channel gallium nitride transistors may be utilized in wireless power/charging devices for improved efficiencies, longer transmission distances, and smaller form factors, when compared with wireless power/charging devices using silicon-based transistors.