Study of electronic, thermoelectric, and optical response of zinc oxynitride thin films

Abstract

In this research work, we have used density functional theory (DFT) and experimental approaches to explore the impact of nitrogen substitution on the electronic, thermoelectric, optical and structural aspects of Zn Ox=1−y Ny compounds with varying dopant content. The ZnO band gap was shown to progressively decrease with the successive increases in N concentration in theoretical and experimental estimated results. The thermoelectric properties of pristine and N-doped ZnO compositions were analyzed by employing Boltztrap measurements. The structural, morphological, and optical properties of sputtered thin films were studied extensively. X-ray diffraction studies exhibited the monophasic hexagonal wurtzite structure without any secondary phase. Field emission scanning electron microscopy was performed to examine the surface morphologies of the prepared thin films, which depicted that the higher dopant content caused grain agglomeration. Optical parameters were extracted using spectroscopic ellipsometry measurements and the optical band gap was inferred using Tauc plot. Importantly, the sample having maximum dopant content revealed tunable ENZ response in the NIR region. It is anticipated from computed simulation and experimental outcomes that the electronic, optical, and thermoelectric behavior of ZnO compounds could be enhanced by ensuing nitrogen inclusion. These engineered materials would be well-suited for optoelectronic applications within the visible and near-infrared energy regions as well as in thermoelectric applications.