Photodiodes based on InAs/InAsSb/InAsSbP heterostructures with quantum efficiency increased by changing directions of reflected light fluxes

It is shown, using the example of InAs/InAsSb/InAsSbP heterostructures, that the formation of a curvilinear reflecting surface consisting of hemispherical etch pits on the rear side of a photodiode chip leads to an increase in the quantum efficiency of photodiodes by a factor of 1.5–1.7 in the entire mid-IR wave-length interval studied ($\lambda$ = 3–5 $\mu$m). For the obtained photodiodes with a cutoff wavelength of 4.8 $\mu$m, a photosensitive area of 0.1 mm$^2$, and a chip area of 0.9 mm$^2$, a monochromatic responsivity at $\lambda$ = 4.0 $\mu$m reached 0.6 A/W, while a dark current at a reverse bias voltage of 0.2 V was within 4–6 A/cm$^2$.