Infrared detection from GaInAs/InP nanopillar arrays

We report on the photoresponse from large arrays of 40 nm radius nanopillars with sensitivity in the long-wavelength infrared regime. Using photoluminescence techniques, a peak wavelength blue shift of approximately 5 meV was observed at 30 K from GaInAs/InP nanopillar structures, indicating carrier confinement effects. Responsivity measurements at 30 K indicated peak wavelength response at about 8 νm with responsivity of 420 mA W^-1 at -2 V bias. We have also measured the noise and estimated the peak detectivity to be 3 × 10⁸ cm Hz^1/2 W^-1 at 1 V reverse bias and 30 K. A maximum internal quantum efficiency of 4.5% was derived from experiment. Both the photo and the dark transport have been successfully modelled as processes that involve direct and indirect field-assisted tunnelling as well as thermionic emission. The best agreement with experiment was obtained when allowances were made for the non-uniformity of barrier widths and electric field heating of carriers above the lattice temperature.