Extended wavelength dilute-bismide infrared nBn photodetectors on InSb

Bismuth incorporation into InSb has the potential to fill a significant technological gap for narrow bandgap III-V alloys that can be grown directly on commercially available substrates with tunable long-wave infrared bandgap energies for sensing applications. Here, we demonstrate the first InSbBi photodetector with a unipolar barrier grown directly on InSb substrates. With only 1% bismuth incorporation, the InSbBi photodetector demonstrated a significant extension in cutoff wavelength of >1 μm beyond that of a nominally identical InSb detector at 79 K. A peak external quantum efficiency of 6% was measured for the InSbBi detector. Pathways to high-performance InSb-based dilute-bismide detectors are presented via (1) quaternary dilute-bismide absorbers and barriers with minimal strain and optimized band alignments or (2) enhanced absorption in detectors with ultra-thin absorbers via refractive index engineering. The work presented highlights the potential of InSbBi nBn detectors as an alternative emerging candidate for long-wave infrared photodetection.