Current-voltage measurements were used to study the electrical and hydrogen sensing characteristics of Pd Schottky contacts fabricated on ZnO. The ZnO films were grown on doped GaAs by MOCVD. By utilizing the GaAs substrate as a low resistance contact to the ZnO film, a remarkably low series resistance of the diodes was achieved. After exposure of the Schottky diodes to a hydrogen ambient, the current at reverse bias increased, indicating the sensitivity to hydrogen gas. In contrast to previous reports, the contacts are able to recover fully at room temperature. Annealing studies in hydrogen ambient show stability of these contacts up to temperatures of 150 • C.

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We report on the characterization of ZnO thin films grown by metal organic chemical vapor deposition (MOCVD) using diethyl zinc (DEZ) and tert-butanol (TBOH) as precursors. Substrate temperature proved to be a crucial factor in the crystallization process, as it vastly impacted the structural properties of the samples studied. Highly c-axis oriented films with large grain size (52 nm), low tensile strain (0.6%), uniform substrate coverage and a columnar structure devoid of hexagonal needles were successfully deposited on n-Si (100) substrates. The temperature-dependent luminescence spectra recorded confirmed the excellent quality of the material obtained in this work. Our results so far set TBOH apart as an outstanding oxygen source for the MOCVD growth of ZnO.

We report on the impact the MOCVD VI:II ratio during growth has on the properties of ZnO thin films grown on glass slides using diethyl zinc (DEZ) and tert‐butanol (TBOH) as precursors. Our work displays the critical effect of this growth parameter on the defects located in the crystal lattice. Oxygen vacancies and other oxygen‐induced defects are shown to affect the films' tensile strain, stress, grain size, bandgap structure, and dispersion properties. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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