Zn3As2 layers grown by liquid phase epitaxy (LPE) on InAs(110) substrates have been irradiated with 100 MeV Ni9+ ions. Irradiation was performed at liquid nitrogen temperature (77 K) with different ion fluences of 1 x 10(10), 1 x 10(11), 1 x 10(12) and 1 x 10(13) ions/cm(2). The structural, electrical and optical properties of the as-grown and Ni9+ ion-irradiated epilayers were Studied by X-ray diffraction (XRD), high-resolution X-ray rocking curve (HRXRD), infrared (IR) optical absorption and Hall measurements. XRD pattern revealed the presence of buried nickel layer between the epilayer and the substrate at the highest fluence of irradiation and the same has been confirmed by cross-sectional scanning electron microscopy and energy-dispersive X-ray microanalysis. IR optical absorption spectra showed a decrease in the bandgap of the epilayers from 1.0 to 0.93 eV on increasing the fluence of irradiation. The unintentionally doped as-grown p-type epilayers changed to n-type due to Ni9+ ion irradiation at the highest fluence of irradiation with the increase of ion fluence. (C) 2008 Elsevier B.V. All rights reserved.