The surfaces of InP were investigated with XPS before and after irradiation by soft X-rays from a synchrotron radiation source.The experimental results indicate that the radiation damage on the surface of InP is related to the energy and dosage of the soft X-rays
particularly the radiation effect caused by X-rays with energies near the resonant absorption energy of K-shell for P atoms is different from that caused by other X-rays. A qualitative explanation for the results is given.