Optical investigations of Be doped ZnO films grown by molecular beam epitaxy

•The optical properties of Be doped ZnO films were investigated.•Low temperature photoluminescence spectrum was dominated by D°X and DAP emissions.•Shallow acceptor state with ionization energy of 116 meV was found in ZnO:Be films.•It is suggested that the incorporated Be atom might favor formation of Zn vacancies defects.•This work demonstrates that N doping BeZnO might be suitable for fabricating reliable p-type ZnO materials.

In this article, the optical properties of ZnO:Be films grown by plasma-assisted molecular beam epitaxy were investigated by the excitation density-dependent and temperature-dependent photoluminescence measurements. The low temperature photoluminescence spectra showed a dominant excitons bound to neutral donors (D°X) emission centered at 3.3540 eV and strong donor-acceptor pair (DAP) transitions at 3.3000 eV. In addition, it showed that the intensity ratio of the DAP and D°X peaks changed with background electron concentration. Furthermore, a shallow acceptor state with ionization energy of 116 meV was found and attributed to Zn vacancy. The present study further suggests that Be and N codoping ZnO might be suitable for fabricating reliable p-type ZnO materials.

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