Abstract
Background: ZnO is well-known for its versatile applications in the semiconductor industry. The recently discovered polymorphs of ZnO are, therefore, attracting significant research and commercial interest to further extend their applications to modern technological devices and gadgets.
Method: Using density functional theory based full potential linearized-augmented-plane-wave-pluslocal- orbital method, we performed calculations for the electronic and optical properties of various polymorphs of ZnO. The modified Becke-Johnson exchange potential and generalized gradient approximation by Perdew et al. are used for the treatment of exchange-correlation energy in the pursuit of the present calculations.
Results: The band-structure results revealed them wide band gap semiconductors with band gap amounting to 2.99eV, 3.20eV, 2.86eV and 3.38eV for Sphalerite, GeP, NiAs and β-BeO type structured ZnO, respectively. Among them, Sphalerite, NiAs and β-BeO type polymorphs of ZnO exhibited direct band gap, whereas the band-gap of GeP-type ZnO was found to be of indirect nature.
Conclusion: These polymorphs of ZnO exhibit interesting electronic and optical properties and are likely important for applications in optoelectronic devices. We believe that this study will contribute as an important reference for the applications of the different polymorphs of ZnO in designing electronic and optoelectronic devices.
Keywords: DFT, ZnO polymorphs, electronic structure, dielectric function, absorption spectra, optoelectronic.
Graphical Abstract
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