A resonant tunneling FET including a heterostructure FET with a channel layer having a first current contact and a control contact operatively coupled thereto and a resonant tunneling device, including a quantum well layer sandwiched between barrier layers with a resonant tunneling layer affixed to an opposite side of one barrier layer, operably affixed to the heterostructure FET to form a second current contact. The resonant tunneling FET being constructed from a material system which allows the fabrication of additional devices on the same substrate.