MCT heterostructures for higher operating temperature infrared detectors designed in Poland

This paper presents examples of infrared detectors with mercury cadmium telluride elaborated at the Institute of Applied Physics, Military University of Technology and VIGO Photonics S.A. Fully doped HgCdTe epilayers were grown with the metal organic chemical vapour deposition technique which provides a wide range of material composition covering the entire infrared range from 1.5 mu m to 14 mu m. Fundamental issues concerning the design of individual areas of the heterostructure including: the absorber, contacts, and transient layers with respect to their thickness, doping and composition were discussed. An example of determining the gain is also given pointing to the potential application of the obtained devices in avalanche photodiode detectors that can amplify weak optical signals. Selected examples of the analysis of current-voltage and spectral characteristics are shown. Multiple detectors based on a connection in series of small individual structures are also presented as a solution to overcome inherent problems of low resistance of LWIR photodiodes. The HgCdTe detectors were compared with detectors from III-V materials. The detectors based on InAs/InAsSb superlattice materials achieve very comparable parameters and, in some respects, they are even superior to those with mercury cadmium telluride.

Automated summary

This paper presents infrared detectors based on mercury cadmium telluride grown using the metal organic chemical vapour deposition technique. The design of individual areas of the heterostructure, including the absorber, contacts, and transient layers, is discussed. The paper includes examples of gain determination, current-voltage and spectral characteristics analysis, and solutions to overcome the low resistance of LWIR photodiodes by connecting multiple small individual structures in series. The performance of the HgCdTe detectors is compared with detectors based on InAs/InAsSb superlattice materials, which show comparable or superior parameters.