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

Abstract

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 (λ = 3-5 μm). For the obtained photodiodes with a cutoff wavelength of 4.8 μm, a photosensitive area of 0.1 mm 2 , and a chip area of 0.9 mm 2 , a monochromatic responsivity at λ = 4.0 μm 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 .

High Quantum Efficiency Nanopillar Photodiodes Overcoming the Diffraction Limit of Light

“…The cutoff wavelength (λ) of our NP PDs is around 3000 nm, which is strong evidence for plasmonically enhanced absorption overcoming the diffraction limit of the light because NPs partially covered with metal absorb longer wavelengths within the extreme subwavelength-scale diameter of NP (below λ/16) through the LSP resonances, whereas the bare NPs show a near zero absorption beyond 1500 nm wavelength (see Figure 5). Further evidence for plasmonically enhanced absorption is the occurrence of the enhanced where the quantum efficiency reaches ∼29% at a reverse bias of 0.15 V. The quantum efficiency of NP PDs is comparable with the planar PDs using 2.5-μm-thick InAs 0.88 Sb 0.12 layer, 31 which exhibit the quantum efficiency of 19% and 25% at wavelengths of 4000 and 2400 nm, respectively, and operate at room temperature. We also compared the measured response of commercial InSb detector with our NP PDs in Supporting Information (see Figure S8).…”

“…These peaks are completely absent from the simulated absorption of bare nanopillars as shown in Figure c. The inset shows the quantum efficiency at 2390 nm as a function of reverse bias, where the quantum efficiency reaches ∼29% at a reverse bias of 0.15 V. The quantum efficiency of NP PDs is comparable with the planar PDs using 2.5-μm-thick InAs 0.88 Sb 0.12 layer, which exhibit the quantum efficiency of 19% and 25% at wavelengths of 4000 and 2400 nm, respectively, and operate at room temperature. We also compared the measured response of commercial InSb detector with our NP PDs in Supporting Information (see Figure S8).…”