Mechanism of the Generation of Donor–Acceptor Pairs in Heavily Doped n-ZrNiSn with the Ga Acceptor Impurity

Abstract

The nature of the mechanism of the simultaneous generation of donor–acceptor pairs under heavy doping of n-ZrNiSn intermetallic semiconductor with the Ga acceptor impurity is established. Such spatial arrangement in the crystal lattice of ZrNiSn_1–xGa_x is found when the rate of movement of the Fermi level εF found from calculations of the density distribution of electron states coincides with that experimentally established from dependences lnρ(1/T). It is shown that when the Ga impurity atom (4s²4p¹) occupies the 4b sites of Sn atoms (5s²5p²), structural defects of both acceptor nature and donor nature in the form of vacancies in the 4b site are simultaneously generated. The results are discussed in the scope of the Shklovskii–Efros model of a heavily doped and compensated semiconductor.