We investigate high-temperature and high-frequency operation of interband cascade infrared photodetectors (ICIPs)-two
critical properties. Short-wavelength ICIPs with a cutoff wavelength of 2.9 μm had Johnson-noise limited detectivity of
5.8×109 cmHz1/2/W at 300 K, comparable to the commercial Hg1-xCdxTe photodetectors of similar wavelengths. A
simple but effective method to estimate the minority carrier diffusion length in short-wavelength ICIPs is introduced.
Using this approach, the diffusion length was estimated to be significantly shorter than 1 μm at high temperatures,
indicating the importance of a multiple-stage photodetector (e.g., ICIPs) at high temperatures. Recent investigations on
the high-frequency operation of mid-wavelength ICIPs (λc=4.3 μm) are discussed. These photodetectors had 3-dB
bandwidths up to 1.3 GHz with detectivities exceeding 1x109 cmHz1/2/W at room temperature. These results validate the
ability of ICIPs to achieve high bandwidths with large sensitivity and demonstrate the great potential for applications
such as: heterodyne detection, and free-space optical communication.
Interband cascade (IC) lasers take advantage of the broken band-gap alignment in type-II quantum wells to reuse injected electrons in cascade stages for photon generation with high quantum efficiency, while retaining interband transitions for photon emission without involving fast phonon scattering. As such, the threshold current density can be significantly lowered with high voltage efficiency, resulting in low power consumption. After about 18 years of exploration and development, IC lasers have now been proven to be capable of continuous wave operation at room temperature and above for a wide wavelength range of 2.9 to 5.7 μm in the mid-infrared spectral region. Here, we present our recent progress in InAs-based IC lasers, which use plasmon cladding layers to replace superlattice cladding layers, resulting in improved thermal dissipation and extended lasing wavelengths.