Deep emission centers in Ge-implanted GaAs

Abstract

Photoluminescence emission spectra from Ge‐implanted layers in GaAs were studied with respect to changes of exciting wavelength, excitation intensity, temperature, and the depth of the implanted layers. Deeper emissions are dominant in the near‐surface region because vacancies and their complexes with Ge play important roles in the radiative processes. Emission due to donor‐acceptor pair transition involving the Ge acceptor is present in all Ge‐implanted layers. The binding energy of the Ge acceptor is estimated to be 40±3 meV from the temperature dependence of the emission due to conduction‐band–to–Ge‐acceptor transitions. High‐temperature annealing at 900–950 °C with a Si₃N₄ cap is needed to increase the Ge activation which produces p‐type conduction.