Sharp line donor–acceptor pair luminescence in silicon

Abstract

New sharp line structure observed in the near-band-edge (1030 to 1135 meV) photoluminescence of Si(P, In) and Si(B, In) at temperatures ranging from 1.6 to 20 K, has been identified as due to radiative recombination of electrons bound to phosphorus donors with holes bound to indium acceptors. This is the first study of sharp line, donor–acceptor pair luminescence in silicon. Straightforward analysis, assuming only Coulomb and van der Waals interactions between otherwise isolated donor and acceptor centres indicates that recombination involving P and In centres separated by distances ranging from 7.7 to 20 Å is responsible for the observed sharp line structure. This structure is superimposed on the high energy shoulder of the broad band luminescence associated with recombination involving distant (average separation: 55 Å) P–In pairs. Transient measurements indicate decay times ranging from 70 to 100 μs for the most prominent sharp lines and an overall decay pattern consistent with that expected for donor–acceptor pair recombination.