Molecular beam epitaxial growth and performance of integrated two-color HgCdTe detectors operating in the mid-wave infrared band

The first report of molecular beam epitaxial growth and performance of HgCdTe two-color detectors for the simultaneous detection of radiation at 4.1 and 4.5 μm is presented. In-situ doped devices with the n-p-n architecture were grown by molecular beam epitaxy on (211)B CdZnTe substrates. Representative structures exhibited x-ray rocking curves with full width at half-maxima of 40–60 arcs. The typical near surface etch pit density in these structures were 4−7 × 106 cm−2. The devices were processed as mesa diodes and electrical contacts were made to the two n-type layers and the p-type layer to facilitate simultaneous operation of the two p-n junctions. The spectral response characteristics of the devices were characterized by sharp turn-on and turn-off for both bands, with R0A values >5 × 105 ωcm2 at 77K. The detectors exhibited quantum efficiencies >70% in both bands.