Photoluminescence of iodine-doped ZnTe homoepitaxial layer grown by metalorganic vapor phase epitaxy

Photoluminescence (PL) properties of I-doped ZnTe homoepitaxial layers grown by atmospheric pressure metalorganic vapor phase epitaxy have been investigated as a function of n-butyliodide (n-BuI) transport rate. The PL spectrum changed drastically even when a low dopant transport rate was used. A structured emission band at 2.22 eV was detected predominantly at low n-BuI transport rates, whereas a structureless broad emission band at around 2.17 eV or less dominates the PL spectrum at high n-BuI transport rates. PL spectra of I-doped ZnTe layers were analyzed at varying excitation power and temperature. These luminescence bands are due to donor–acceptor pair recombination, and may be ascribed to complexes consisting of Zn vacancies and I on Te sites close to donors.