Shallow donor levels of Li-doped ZnSe single crystals
Li-doped Zincselenide (ZnSe) single crystals with various Li concentrations were grown by the sublimation method. Three types of donoracceptor pair (DAP) bands with their phonon replica are observed in their photoluminescence (PL) spectra at 4.2 K. As the Li concentrations increase, the DAP bands seems to shift to the lower energy side. From the excitation intensity and the temperature dependence of PL spectra, three kinds of constituent donors with the activation energies of 17, 28 and 50 meV are detected. It will be proposed that the origins of donors are Lii (Li interstitials), ClSe (substitutional Cl in Se sites) and complex donors, respectively. These donors become dominant, in turn, to form DA pair recombination as the Li concentrations increase.
znse donoracceptor pair (dap) photoluminescence (pl) activation energy free-to-acceptor (fa) material