Antimonide based materials for infrared detection

We propose that the antimonide family of semiconductors should be considered in some cases as a serious alternative to Mercury Cadmium Telluride (MCT) for the active region of next generation IR detectors, based on epitaxial materials. Among the alloys, epitaxial InAs_1-ySb_y on GaSb with 0.07 <y < 0.11 and In_1-zAl_zSb on InSb with 0 < z < 0.03 together span important regions of the MWIR atmospheric window, yet exhibit strains of less than 0.15%. Both InSb and GaSb are binary substrates available in high quality. The sensitivity of bandgap to composition in In_1-zAl_zSb is similar to that in MCT. However, in InAs_1-ySb_y this sensitivity is more than halved. In growth from the gas phase, the constraints on temperature stability are about 3-5 times lower than in MCT. Together, these characteristics make it easier to achieve high uniformity, particularly in InAs_1-ySb_y. Finally, high quality superlattices based on InAs/Ga_1-xIn_xSb can be grown by lattice matching to GaSb. This epitaxial material is emerging as an attractive alternative to MCT with a high degree of spatial uniformity and with an ability to span cut-off wavelengths from 3-20μ, in a single material system.