Lattice disorder was produced by fast neutrons at a fluence of 2.1 x 1018/cm2, and was investigated using 1.5MeV 4He+ channelling. A slight increase in the <111> aligned yield for irradiated crystals indicated that each primary knock-on produced some 700 displaced atoms. The channelling data also revealed a spread of randomly located defects that were embedded in the lattice. The P antisite defects which were produced by neutron irradiation amounted to 2 per primary knock-on. The irradiated samples also exhibited a volume expansion of 0.13%. It was suggested that this lattice expansion was caused mainly by vacancy-interstitial clusters that arose from the displaced atoms, rather than PGa defects.

Ion Channelling Study of the Lattice Disorder in Neutron Irradiated GaP K.Kuriyama, Y.Miyamoto, T.Koyama, O.Ogawa, M.Okada: Journal of Applied Physics, 1999, 86[4], 2352-4