Response of an acoustic charge transport device to near-infrared radiation

We have studied the response of a GaAs Acoustic Charge Transport (ACT) device to near-infrared radiation (λoptical= 730nm). One motive was the possibility that an ACT device might be used to resolve spatial radiation distributions. Experiments were undertaken using an ACT device fabricated with four thin (25nm) regularly spaced semi-transparent chromium windows along an otherwise opaque Schottky channel plate. Focussed optical pulses over each window gave rise to a delayed output current response in accordance with the injection position and the surface acoustic wave (SAW) velocity. Quantum efficiency, defined as the number of electrons collected at the output node per incident photon on the semi-transparent window, was 0.09.