Resonant-cavity-enhanced HgCdTe photodetectors

Resonant cavity enhanced HgCdTe structures have been grown by molecular beam epitaxy, and photoconductors have been modelled and fabricated based on these structures. Responsivity has been measured and shows a peak responsivity of 8 x 10⁴ V/W for a 50 X 50 μm² photoconductor at a temperature of 200K. The measured responsivity shows good agreement with the modelled responsivity across the mid-wave infrared window (3-5μm). The measured responsivity is limited by surface recombination, which limits the effective lifetime to ~15ns. The optical cut-off of the detector varies with temperature as modelled from 5.1 um at 80K to 4.4 um at 250K. There is strong agreement between modelled and measured peak responsivity as a function of temperature from 80-300K.