All-epitaxial guided-mode resonance mid-wave infrared detectors

We demonstrate all-epitaxial guided-mode resonance mid-wave infrared (MWIR) type-II superlattice nBn photodetectors. Our detectors consist of a high-index absorber/waveguide layer grown above a heavily doped ( n + +), and thus, low-index, semiconductor layer, and below a high-index and wide-bandgap grating-patterned layer. Polarization- and angle-dependent detector response is measured experimentally and simulated numerically, showing strongly enhanced absorption, compared to unpatterned detectors, at wavelengths associated with coupling to guided-mode resonances in our fabricated detectors. The detectors show high operating temperature (T = 200 K) external quantum efficiencies over 50% for TE-polarized light with absorber thickness of only 250 nm ( ∼ λ o / 20). We calculate T = 200 K estimated specific detectivity for our detectors, on resonance, of ∼ 4 × 1 0 10 cm H z 1 / 2 W − 1, comparable with state-of-the-art MWIR detectors. The presented results offer an approach to monolithic, all-epitaxial integration of IR detector architectures with resonant optical cavities for enhanced detector response across the mid-wave infrared.