Opto-electro-mechanical properties of Al-doped Zinc Oxide

Due to the advanced technological applications that fulfill human daily life needs, the importance of interdisciplinary research is extensively growing. In material science and engineering, employing a material possessing outstanding properties in various fields is of great interest. Among these materials, zinc oxide (ZnO) has the potential for having interesting optical, piezoelectric, and mechanical features. Despite the massive research to show the capabilities of ZnO, some of its derivatives lack investigations regarding their multi-physical properties. One of these compounds is Al-doped ZnO (AZO), well-known for its unique optical properties [1] but still unknown for mechanical features. In this work, we aim to seek the Opto-electro-mechanical properties of AZO by utilizing the ab-initio density functional theory technique. Specifically, we provide a theoretical method for calculating the elastic constant of any hexagonal crystal structure from atomic-scale simulations, including ZnO. To this end, we perform DFT energy calculations, including structural relaxation of pure and different Al atomic percentages of AZO, to find the crystal structure with minimum energy for LDA exchange-correlation functional. To calculate the elastic and mechanical characteristics, we apply a set of different strain matrices to the lattice vectors of ZnO (AZO) crystal structures. The extracted optical, electronic, and mechanical properties are compared with other experimental and theoretical works in the literature to verify the methodology used in this research. The generated optomechanical data, including optical dispersion functions and elastic constant matrices of pure and Al-doped ZnO, are suitable for larger-scale differential equation solvers such as the finite-element method for device modeling of any optomechanical system made of ZnO (AZO). In this way, we can readily predict the proposed compounds? optomechanical functionality while avoiding existing limitations in experimental works.

[1] Shabani, A., Khazaei Nezhad, M., Rahmani, N., Mishra, Y.K., Sanyal, B., & Adam, J. (2021). Revisiting the optical dispersion of aluminum?doped zinc oxide: new perspectives for plasmonics and metamaterials. Advanced Photonics Research, 2(4), [2000086]. https://doi.org/10.1002/adpr.202000086