Mitsubishi has reportedly developed graphene-based MWIR sensors with extraordinarily high sensitivity. Thanks to an internal graphene FET gain, the responsivity is said to be 10 times higher than that of quantum-type IR sensors with no internal amplification. Mitsubishi uses graphene FET and leverages its high electron mobility.
Other than a graphene-based FET, reports suggest that there is "a light-amplifying part" that produces photoelectrons and photoholes and is placed under the graphene. At a very low temperature of, for example, 80K, the responsivity increases even more, by a factor of 100x.
Mitsubishi is also reportedly developing LWIR sensors using a dielectric for the light-amplifying. Existing quantum-type LWIR sensors reduce thermal noise by cooling down to liquid nitrogen temperature. Mitsubishi claims that with its new method, the sensor might be able to work at room temperature.