GaAsSbN layers with small lattice mismatch to GaAs were studied for possible application as the intrinsic layer in a GaAs-based p-i-n photodetector. Our calculation has shown that small lattice mismatch GaAsSbN to GaAs could be achieved at an Sb/N atomic ratio of 2.60. GaAsSbN was grown as the intrinsic layer for a GaAs/GaAsSbN/GaAs photodetector structure using solid-source molecular beam epitaxy in conjunction with a radio frequency (rf) plasma-assisted nitrogen source and valved antimony cracker source. The lattice mismatch of the GaAsSbN layer to GaAs was kept below 5000 ppm, which is sufficient to maintain coherent growth of similar to 0.5 Am thick GaAsSbN on GaAs substrate. The growth temperature was varied between 420 and 520 degrees C, and the Sb flux beam equivalent pressure between 1.7 X 10(-8) and 2.3 X 10(-8) Torr to maintain coherent growth. All samples exhibit room temperature photocurrent response in the 1.3 Am wavelength region. X-ray diffraction two-dimensional maps showed diffuse scattering, which may have been caused by point defects in the material. (c) 2005 American Vacuum Society.