Oxygen incorporation in ZnTeO alloys via molecular beam epitaxy

Highly mismatched ZnTeO alloys were grown by molecular beam epitaxy under various oxygen partial pressures (10-7 Torr, 10-6 Torr, and 10-5 Torr). Despite this large variation in oxygen partial pressure, there was almost no change in the concentration of incorporated oxygen. However, increasing the oxygen partial pressure significantly enhanced the photoluminescence of the oxygen-related transition at 1.9 eV. The evolution of lattice constants, as determined by high-resolution x-ray diffraction, appeared to follow Vegard's law for ideal substitutional alloys for ZnTeO films prepared at 10-7 Torr and 10-6 Torr, while a pronounced deviation occurred at 10-5 Torr. Channeling nuclear reaction analysis further revealed the complexity of oxygen incorporation, as no significant shadowing was observed from the epitaxial films. The evidence suggests that the oxygen location in ZnTeO is more complicated than O-Te substitutional defects in a homogeneous solid solution, and that the configuration of the oxygen dopant might play an important role in the band structure and optical properties of the alloys. © 2014 TMS.