An Experimental Analysis on Structural, Morphological, Optical, and Thermal Properties of Reduced Graphene Oxide Decorated Mg-Doped ZnO Thin Film Nanostructures for Thermal Management Applications

Efficient thermal management is vital for high-power electronics. This study investigates the interfacial thermal transport of reduced graphene oxide (rGO) decorated magnesium‑doped zinc oxide (MZO) thin films, fabricated on aluminum substrates via a scalable sol-gel and dip-coating process. Structural characterization confirmed the synthesis of a highly crystalline wurtzite MZO matrix exhibiting strong interfacial interactions with a graphitic rGO network. XRD analysis showed increased residual tensile stress, peaking at 1.42 GPa for the 1.0 rGO/MZO composite, indicating strong mechanical interlocking. Spectroscopic analysis revealed a systematic hypsochromic blue shift (592 to 599 cm−1) in Zn–O stretching and optical band gap narrowing to 3.24 eV. These features suggest intimate electron-phonon coupling and the formation of a percolated conductive network. Thermally, the 1.0 rGO/MZO composite demonstrated superior heat dissipation, reaching a maximum saturation temperature of 60.8°C during resistive heating and enhancing heat spreading in LED cooling tests. The superior performance is hypothesized to stem from a dual-mechanism: the potential reduction of interfacial thermal boundary resistance via structural coupling, and the formation of continuous heat conduction pathways by the rGO network, which may help mitigate grain boundary scattering. Ultimately, these findings position rGO/MZO nanocomposites as highly promising candidates for next-generation thin film heat spreaders in high-power electronic applications.