Identification of donor species in high-purity GaAs using optically pumped submillimeter lasers

An optically pumped NH3 laser has been used in conjunction with careful doping experiments in high-purity GaAs to determine the ionization energy of isolated tin donors. The energy obtained is 5.820 meV, which corresponds to a central-cell correction of 0.081 meV. This technique for impurity analysis is estimated to be sensitive to donor concentrations of less than 1011 cm−3.