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  Friedrich, F. ; Sieber, I. ; Klaus, M. ; Genzel, Ch.; Nickel, N.H.: Pulsed-laser deposition of ZnO thin-films on MgO substrates. Physica Status Solidi C 5 (2008), p. 3288-3292

Abstract:
Zinc oxide thin-films were grown by laser deposition technique on (111)- and (100)-oriented magnesium oxide substrates (MgO). The deposition temperature was varied between 600 and 860°C. In this temperature range the formation of Mg(OH)2 is thermodynamically unfavorable which prevents a degradation of the MgO surface. The films were characterized by scanning electron microscopy, Raman spectroscopy, and X-ray diffraction. The results show that high-quality c-axis oriented ZnO thin-films were grown on (111)-oriented MgO. On (100)-oriented MgO a more complex ZnO thin-film formation was observed. At lower growth temperatures grains of different orientation were identified. Grains with orientations that deviated from (001) contain more residual stress, which manifests itself in a shift of the E2high phonon mode position to 442 cm-1. With increasing growth temperature the film structure becomes more uniform and at 860°C large areas of either (001) or (101) orientation were found. The results also indicate that no amorphous ZnO buffer layer is formed at the interface.