New concepts in infrared photodetector designs

In 1959, Lawson and co-workers published the paper which triggered development of variable band gap Hg1-xCdxTe (HgCdTe) alloys providing an unprecedented degree of freedom in infrared detector design. HgCdTe ternary alloy has been used for realization of detectors operating under various modalities including: photoconductor, photodiode, and metal-insulator-semiconductor detector designs. Over the last five decades, this material system has successfully overcome the challenges from other material systems. It is important to notice that none of these competitors can compete in terms of fundamental properties. The competition may represent more mature technology but not higher performance or, with the exception of thermal detectors, higher operating temperatures (HOTs) for ultimate performance. In the last two decades, several new concepts for improvement of the performance of photodetectors have been proposed. These new concepts are particularly addressing the drive towards the so called HOT detectors aiming to increase detector operating temperatures. In this paper, new strategies in photodetector designs are reviewed, including barrier detectors, unipolar barrier photodiodes, multistage detectors and trapping detectors. Some of these new solutions have emerged as a real competitor to HgCdTe photodetectors. (C) 2014 AIP Publishing LLC.