Photoluminescence Studies of Mg-Doped and Si-Doped Gallium Nitride Epilayers

Abstract

We present time-, temperature- and intensity-dependent photoluminescence measurements of undoped, n-type and p-type GaN epilayers. In the nominally undoped samples we observe at low temperatures the trapping of free excitons by neutral donors and subsequent radiative recombination. In the n-type Si-doped samples bound-exciton luminescence is dominant over a wide range of temperatures. The luminescence from p-type Mg-doped samples is dominated by shallow-donor–shallow-acceptor pair recombination and by a deep blue centres at 3.0 eV. These two emission bands show identical temperature and linear intensity dependence.