An implant-free enhancement mode metal-oxide semiconductor field effect transistor (EMOSFET) is provided. The EMOSFET has a III-V compound semiconductor substrate and an epitaxial layer structure overlying the III-V compound semiconductor substrate. The epitaxial material layer has a channel layer and at least one doped layer. A gate oxide layer overlies the epitaxial layer structure. The EMOSFET further includes a metal gate electrode overlying the gate oxide layer and source and drain ohmic contacts overlying the epitaxial layer structure.