Photoluminescence of Cl-doped ZnTe epitaxial layer grown by atmospheric pressure metalorganic vapor phase epitaxy

Effects of Cl doping on the photoluminescence (PL) of ZnTe homoepitaxial layers grown by atmospheric pressure metalorganic vapor phase epitaxy using n-butylchloride (n-BuCl) have been investigated. A quite strong donor bound excitonic emission was observed by increasing the n-BuCl transport rate, implying that Cl is incorporated into ZnTe layer as a donor. From the temperature dependence of PL spectra, the thermal activation energy of donor bound excitonic emission was found to be 5.9 meV. Two luminescence bands due to donor-acceptor pair emission appeared at 2.34 and 2.22 eV in the layer grown at an n-BuCl transport rate as high as 0.2 μmol/min. The donor and acceptor levels corresponding to the PL peak at 2.34 eV were estimated to be 22 and 51 meV from the excitation power dependence of PL peak energy, respectively.