Responsivity and lifetime of resonant-cavity-enhanced HgCdTe detectors

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 × 104 V/W for a 50 × 50 μm2 photoconductor at a temperature of 200 K. The measured responsivity shows some agreement with the modelled responsivity across the mid-wave infrared window (3–5 μm). The measured responsivity is limited by surface recombination, which limits the effective lifetime to ≈15 ns. The optical cut-off of the detector varies with temperature as modelled from 5.1 μm at 80 K to 4.4 μm at 250 K. There is strong agreement between modelled peak responsivity and measured peak responsivity with varying temperature from 80 to 300 K.