Native Point Defects and Nonstoichiometry in GaAs (II) Mechanism of Formation and Degradation of Semiinsulating Properties of Undoped Gallium Arsenide Crystals

Abstract

AbstractThe nature of the main electron trap, EL2, in undoped semiinsulating GaAs crystals have been studied both qualitatively and quantitatively. It has been shown that point defects which, most probably, are responsible for the EL2 level are antisite AsGa defects or (AsiVGs) complexes which are indistinguishable from the thermodynamic standpoint. The enthalpy and entropy of AsGa formation according to the reaction AsAs + VGa ⇄ AsGa + VAs are equal to 0.5 eV and −7k, respectively.