Abstract: A quantum interference semiconductor device comprises a channel layer of a first semiconductor material, a carrier supplying layer of a second semiconductor material provided on the channel layer and whereby a two-dimensional carrier gas is formed in the channel layer along an upper major surface thereof, a source electrode provided on the carrier supplying layer for injecting carriers, a drain electrode provided on the carrier supplying layer and displaced from the source electrode in a first direction defining a region of the channel layer therebetween which collects the injected carriers after travelling through the carrier gas in the first direction and a gate electrode structure provided on the region of the carrier supplying layer and in Schottky contact therewith.