Photoluminescence of arrays of self-induced nanowires consisting of pure InAs and of InAs diluted with nitrogen was studied in the 4.2–300 K temperature range. Formation of the hexagonal wurtzite (nanowires) and cubic sphalerite  (mostly parasitic islands) crystal structure modifications was observed on a Si substrate used for the growth of the nanowires. A decrease in the band gap of both crystalline phases due to the introduction of nitrogen was established.