Analysis of Barrier Parameters on the Extended Threshold Wavelength of Infrared Detectors

The threshold wavelength (λ
_t
) of spectral photoresponse of any semiconductor photodetector is determined by the minimum energy gap (Δ = 1.24/λ
_t
) of the material, or the interfacial energy gap of the heterostructure. It was shown before that the threshold limit can be extended beyond λ
_t
to obtain an extended threshold wavelength λ
_eff
(λ
_eff
≫ λ
_t
) in detectors with a barrier energy offset (δE
_v
) and a gradient. Here, in this letter, we analyze the effect of barrier parameters such as δ E
_v
and gradient on the extended threshold wavelength of infrared detectors for the temperature range up to 50 K.