A positron annihilation and Hall effect study of vacancy defects in III-V compound semiconductors. I. Gallium phosphide

Abstract

Positron lifetime and Hall effect measurements have been performed to study vacancy defects in GaP. No Ga vacancies have been detected, while P vacancies have always been found in as-grown material. They show at least two different ionization levels within the upper half of the bandgap, which have been attributed to VP+/VP0 at EC-ED>400 meV and VP0/VP- at EC=ED=250+or-30 meV, respectively. The concentration of the P vacancies in the as-grown samples was found to be in the order of some 1016 cm-3. The specific positron trapping rate for negatively charged P vacancies was determined as mu vP=(1.9+or-0.5)*1015 s-1.