Effects of thermal annealing on the microstructural properties of the lower region in ZnO thin films grown on n-Si (001) substrates

Abstract

Transmission electron microscopy (TEM) images, selected-area electron-diffraction patterns, high-resolution TEM images, and x-ray energy dispersive spectroscopy line scans for the ZnO/n-Si (001) heterostructures annealed at 900 degrees C showed that stacking faults and amorphous layers were formed in the lower region of the ZnO films. The stacking faults existing in the lower region of the ZnO columnar grains originated from the formation of zinc vacancy layers caused by the thermal treatment, resulting in the existence of a tensile strain. The formation of the amorphous layer in the ZnO film was attributed to the accumulation of zinc vacancy layers.