ZnO thin layers deposited on 6H-SiC substrates showed six-fold crystal symmetry with an epitaxial relationship of (0002)(ZnO)parallel to(0006)(SiC) and [11 (2) over bar0](ZnO)parallel to|[11 (2) over bar0](SiC). Despite the different 6H-SiC substrate surface orientations for the ZnO epitaxy, the orientation relationship of ZnO/6H-SiC heterostructures is identical, as confirmed by X-ray diffraction studies. In these ZnO/6H-SiC(0001) and ZnO/6H-SiC(0 0 0 (1) over bar1) heterostructures, the valence band offsets are measured to be 1.12 eV and 1.09 eV, leading to the conduction band offset values of 0.75 eV and 0.72 eV, respectively. These slightly different band-offset values in ZnO/6H-SiC heterojunctions are attributed to the variation of valence band maximums and the different interface charge compensation mechanisms. (C) 2011 Elsevier B. V. All rights reserved.