Double carriers pulse DLTS for the characterization of electron–hole recombination process in GaAsN grown by chemical beam epitaxy

A nitrogen-related electron trap (E1), located approximately 0.33 eV from the conduction band minimum of GaAsN grown by chemical beam epitaxy, was confirmed by investigating the dependence of its density with N concentration. This level exhibits a high capture cross section compared with that of native defects in GaAs. Its density increases significantly with N concentration, persists following post-thermal annealing, and was found to be quasi-uniformly distributed. These results indicate that E1 is a stable defect that is formed during growth to compensate for the tensile strain caused by N. Furthermore, E1 was confirmed to act as a recombination center by comparing its activation energy with that of the recombination current in the depletion region of the alloy. However, this technique cannot characterize the electron−hole (e–h) recombination process. For that, double carrier pulse deep level transient spectroscopy is used to confirm the non-radiative e–h recombination process through E1, to estimate the capture cross section of holes, and to evaluate the energy of multi-phonon emission. Furthermore, a configuration coordinate diagram is modeled based on the physical parameters of E1.

Research Highlights
► Double carrier pulse DLTS method confirms the existence of SRH center.
► The recombination center in GaAsN depends on nitrogen concentration.
► Minority carrier lifetime in GaAsN is less than 1 ns.
► A non-radiative recombination center exits in GaAsN.