High quality InAs0.83Sb0.17 mid-wavelength infrared p-pi-n photodetector structure was grown with the aid of a GaSb transition layer on semi-insulating GaAs substrate by molecular beam epitaxy. The lattice mismatch and the crystal quality of the structure were investigated by high resolution X-ray diffraction rocking curve measurement. The full width at half maximum values forInAs(0.83)Sb(0.17) and GaSb crystals were determined as 215 and 238 arcsec, respectively. The lattice mismatch between InAs0.83Sb0.17/GaSb structure and GaAs substrate was identified as 8.44%. Activation energies for two different temperature regimes were extracted from Arrhenius plot which was derived from temperature dependent dark current measurements. The dominant dark current mechanisms were determined as generation-recombination limited and surface leakage based for higher- and lower-temperature regimes, respectively. The cut off wavelength and the peak quantum efficiency of the photo detector were obtained from the spectral photoresponse as 4.23 mu m and 243% at 80 K, respectively. (C) 2016 Elsevier B.V. All rights reserved.