SAW DETECTOR

A SAW detector has a SAW transducer 10 disposed on the surface of a piezoelectric substrate 12 which injects a SAW 20 in response to an RF input signal applied to line 14. A semiconductor charge transport region 30 comprising a charge transport channel 32 sandwiched between two charge confinement layers 34,36, is disposed above the substrate. A source electrode 40 provides electrons to the channel 32 and a drain electrode 42 removes electrons from the channel 32. The electric fields generated by the SAW 20 travel along the channel 32 and provide a forcing function to move the electrons from the source electrode to the drain electrode as a continuum, not in charge packets, thereby providing output current 48 on a line 49 indicative of the SAW 20 frequency.