Publications

Recent developments in interband cascade infrared photodetectors

Lotfi, Hossein; Li, Lu; Lei, Lin; Ye, Hao; Rassel, Sm S.; Jiang, Yuchao; Yang, Rui Q.; Klem, John F.; Mishima, Tetsuya D.; Santos, Michael B.; Johnson, Matthew B.; Gupta, James A.

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.