In this work, we employ a simple two-step growth technique to deposit impurity doped heteroepitaxial thin films of (0001) ZnO onto (111) MgAl2O4 spinel substrates through a combination of atomic layer deposition (ALD) and hydrothermal growth. The hydrothermal layer is doped with Al, Ga, and In through the addition of their respective nitrate salts. We evaluated the effect that varying the concentrations of these dopants has on both the structural and optical properties of these films. It was found that the epitaxial ALD layer created a ⟨111⟩MgAl2O4∥⟨0001⟩ZnO out-of-plane orientation and a ⟨1¯1¯2⟩MgAl2O4∥∥⟨011¯0⟩ZnO in-plane orientation between the film and substrate. The rocking curve line widths ranged between 0.75° and 1.80° depending on dopant concentration. The optical bandgap determined through the Tauc method was between 3.28 eV and 3.39 eV and showed a Burstein-Moss shift with increasing dopant concentration.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was funded in part by the Solid-State Lighting Program (SSLP), a collaboration between King Abdulaziz City for Science and Technology (KACST), King Abdullah University of Science and Technology (KAUST), and University of California, Santa Barbara. A portion of this work was carried out in the UCSB nanofabrication facility, with support from the NSF National Nanotechnology Infrastructure Network (NNIN) (ECS-03357650), as well as the UCSB Materials Research Laboratory (MRL), which is supported by the NSF Materials Research Science and Engineering Centers (MRSEC) Program (DMR-1121053).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.