Vacancies and negative ions in as-grown and ion-bombarded p-InP(Zn) observed by positron annihilation
Defects in as-grown and ion-bombarded p-InP crystals have been investigated by positron lifetime measurements. The result showed that indium vacancies existed in as-grown p-InP. In addition, Zn impurities were also observed, which are negative and act as shallow trapping centres at low temperatures. Ion bombardment at lower dose introduced some monovacancies, and with increasing ion dose, divacancies were also observed, which coexisted with monovacancies. The temperature experiment showed that antisite defects were also produced upon bombardment, which we attribute to the negatively charged antisites.