Photoluminescence study of Sb-doped p-type ZnO films by molecular-beam epitaxy

We investigated photoluminescence (PL) from reliable and reproducible Sb-doped $p$ -type ZnO films grown on $n\text{-}\mathrm{Si}$ (100) by molecular-beam epitaxy. Well-resolved PL spectra were obtained from completely dopant-activated samples with hole concentrations above $1.0\times {10}^{18}{\mathrm{cm}}^{-3}$ . From free electron to acceptor transitions, acceptor binding energy of 0.14 eV is determined, which is in good agreement with analytical results of the temperature-dependent PL measurements. Another broad peak at 3.050 eV, which shifts to lower energy at higher temperatures, indicates the formation of deep acceptor level bands related to Zn vacancies, which are created by Sb doping.