A novel voltage tuneable infrared spectrometer-detector

A novel voltage tuneable spectrometer-detector has been demonstrated whose principles are associated with the electric subbands existent at the interface between silicon and silicon dioxide. The photoresistive response of n-channel MOSFET structures to radiation resonant with energy levels in the inversion layer has been characterized and compared with existent theory. Operating at 4.2 K, typical devices have continuous tuneability from 8 MeV (∼150 µm) to 30 MeV (∼40 µm), a bandwidth of approximately 1 MeV, a response time of 2.5 × 10-4s, and a noise equivalent power (NEP) of approximately 2.5 × 10-10W/(Hz)1/2limited by the available amplifiers.