Double-Barrier Superlattice Infrared Photodetectors

We have designed a double-barrier superlattice infrared photodetector (SLIP) which has a superlattice (SL) sandwiched between the thin and thick barriers. Photoelectrons can bounce back and forth between the two barriers and inject through the thin barrier to enhance the photocurrent. However, the supply of electrons is limited by the thick barrier and thus we have to fabricate the emitter contact on the SL. In comparison with the single-barrier SLIP, this structure shows at least one-order higher magnitude of photocurrent at low bias and the associated detectivity is also increased for more than one order. The dramatic increment of the photocurrent is consistent with our design in the detailed analysis. Because it has the optimized performance at low bias, this double-barrier SLIP is suitable for low power consumption applications. Our detector can be operated at 100 K by blocking barriers incorporated into the structure to reduce the dark current.