Deep emissions of MBE-ZnTe on tilted GaAs substrate

The photoluminescence (PL) profiles in deep region of ZnTe grown on tilted GaAs (0 0 1) substrates, 2° off toward 〈1 1 0〉, without ZnSe buffer layer have weak self-activated (SA) emissions at about 1.6–2.0 eV. PL shows the characteristic dependence on the excitation intensity and temperature. The excitation intensity dependence of the PL structure at 2.322 eV shows that the emission structure is due to the donor–acceptor pairs (DAP). The temperature dependence of the DAP emission indicates a two-step thermal quenching process. The zero-phonon line of the phonon replicas of oxygen isoelectronic traps is lowered by 5 meV from that of bulk crystal due to the difference in the thermal expansions between ZnTe and the substrate. The emissions at around 1.65 eV are the SA emissions related to Te-interstitial atoms.