A field effect transistor includes a substrate; an electron channel layer disposed on the substrate; a barrier layer disposed on the electron channel layer; a hole channel layer disposed on the barrier layer; a p-type doped semiconductor material layer disposed on the hole channel layer; a source electrode including a first portion in ohmic contact with the electron channel layer and a second portion in ohmic contact with the p-type doped semiconductor material layer; a drain electrode in ohmic contact with the electron channel layer; and a gate electrode disposed facing the p-type doped semiconductor material layer, between the source and drain electrodes.