Compensation of nitrogen acceptor in ZnSe : N/ZnSe grown by MOCVD

Abstract

It has been proved that the net acceptor concentration as high as 2×10 17 cm −3 can be obtained when ZnSe : N homoepitaxial layers grown by metalorganic chemical vapor deposition (MOCVD) are annealed in molten zinc. However, it was found that the emission intensity of two sets of donor–acceptor pair (DAP), shallow DAP (D sAP) and deep DAP (D dAP), increased with the increase in annealing temperature. In order to clarify the compensation effect, the study on the origin and the concentration of deep donor related to the D dAP emission should be carried out. The ionization energies of acceptor and deep donor were estimated to be 101±1 and 44±5 meV, respectively, by examining the dependence of their emission peaks with the excitation intensity. Furthermore, the upper limit of the deep donor concentration was estimated to be 1×10 16 cm −3. This is one magnitude smaller than the net acceptor concentration obtained from the annealed ZnSe : N homoepitaxial layer in our previous paper. By studying on the behaviors of deep donor, the main reason to lead to a low net acceptor concentration in the ZnSe : N epitaxial layers is not attributed to deep donor complex containing nitrogen atoms, but hydrogen passivation, although a part of doped-nitrogen atoms combine with other defects to form complicated defects.