A uni-terminal transistor device is described. In one embodiment, an n-channel transistor comprises a first semiconductor layer having a discrete hole level H0; a second semiconductor layer having a conduction band minimum EC2; a wide bandgap semiconductor barrier layer disposed between the first and the second semiconductor layers; a gate dielectric layer disposed above the first semiconductor layer; and a gate metal layer disposed above the gate dielectric layer and having an effective workfunction selected to position the discrete hole level H0 below the conduction band minimum Ec2 for zero bias applied to the gate metal layer and to obtain n-terminal characteristics.