Evidence of defect‐annealing effect in swift heavy‐ion‐irradiated indium phosphide

Abstract

Single-crystal indium phosphide (InP) was irradiated by swift heavy ions ( 40 Ar, 56 Fe, 86 Kr, 181 Ta, and 209 Bi) with different energies. The damage evolutions have been investigated by means of Raman spectroscopy and electron microscopy. Analysis of Raman intensity ratio (LO 0 peak to LO peak [I LO 0 /I LO ]) provides a new insight into the lattice quality of the irradiated samples. The defect-activated longitudinal optical mode (LO 0 ) appeared and then disappeared with increasing ion fluences, and it seems that the peak point of I LO 0 / I LO is electronic energy loss dependent. The phenomenological model suggests that the LO 0 peak intensity is positively correlated with the proportion of the activated regions, where the crystals were not completely disordered, but still many defects were created. Furthermore, the TEM images showed that the tracks closely overlapped, resulting in the decrease of activated regions, which implies that there is a competitive mechanism between the generation and annealing of the defects. It also provides direct evidence that the annealing effect of the defects has occurred during the swift heavy-ion irradiation.