High-speed photodetectors’ intrinsic response is limited by the transit time of the carriers that light generates to the contacts that collect these carriers generating an electric response in the external circuitry. By contrast, charge plasma confined in a semiconductor can transfer energy, hence responding much faster, than the field-induced carrier drifts current. The analogy is to a drop exciting a wave in a reservoir, which is detected more rapidly than the drop’s transport by current flow. Here we construct a photodetector device in which charge reservoirs of confined two-dimensional electron and hole gasses (2DEG, 2DHG) mediate the photodetector response circumventing charge transport limitations in both expended energy and required velocity. In response to short optical pulses, this device produces electrical pulses which are almost two orders of magnitude shorter than the same device without the charge …