Heterojunction detectors for terahertz applications

Terahertz imaging is finding a wide range of interest in biology, communications, environment, medicine, security, and space applications. Here results are presented on heterojunction based terahertz detectors covering the range from 1-60 THz. One set of detectors is based on free carrier absorption, followed by internal photoemission aver a workfunction at the interface. These detectors can be produced using any III/V materials and the threshold frequency can be tailored by adjusting the material composition. Examples of GaAs/AlGaAs based detectors with thresholds ranging from 2.3 to 4.2 THz and GaN/AlGaN detectors with threshold of 1 THz are presented. Also briefly mentioned are the quantum dot detectors for the terahertz range.