Vertical field HMSM photodetector

We have previously fabricated δ-doped heterostructure metal-semiconductor-metal (HMSM) photodetectors with a time response below the 10 ps level, which were much faster than devices of equivalent dimensions. Simulation results on static and dynamic aspects of device behavior indicate the improved performance is partially due to the δ-doping layer which transforms the lateral electric field to a vertical orientation. A direct result is that, by following the vertical field, photogenerated electrons reach contacts via the two-dimensional electron gas (2DEG) layer in a much shorter time, thus enhancing the transit time dependent dynamic performance.