Tianchong Zhang

Surface/strain energy balance controlling preferred orientation in CdZnO films

Single-phase rock-salt CdZnO films were synthesized on r-plane sapphire substrates by metal–organic chemical vapor deposition. Evolutions in growth orientations were investigated in these films as a function of Zn content and film thickness. The preferred orientation is found to black (thick) and red (thin) lines depend on the balance between the surface and strain energy accumulated in the films in accordance with the so-called overall energy model. Specifically, (100) orientation dominates below a critical Zn content and/or a critical film thickness, otherwise (111)-oriented grains nucleate on top of the (100) planes.