Considering the excellent tunability of electrical and dielectric properties in binary metal oxide based multi-layered nanolaminate structures, a thermal atomic layer deposition system is carefully optimized for the synthesis of device grade Al₂O₃/TiO₂ nanolaminates with well-defined artificial periodicity and distinct interfaces, and the role of process temperature in the structural, interfacial, dielectric and electrical properties is systematically investigated. A marginal increase in interfacial interdiffusion in these nanolaminates, at elevated temperatures, is validated using X-ray reflectivity and secondary ion mass spectrometry studies. With an increase in deposition temperature from 150 to 300 °C, the impedance spectroscopy measurements of these nanolaminates exhibited a monotonic increment in dielectric constant from ∼95 to 186, and a decrement in dielectric loss from ∼0.48 to 0.21, while the current–voltage measurements revealed a subsequent reduction in leakage current density from ∼2.24 × 10⁻⁵ to 3.45 × 10⁻⁷ A cm⁻² at 1 V applied bias and an improvement in nanobattery polarization voltage from 100 mV to 700 mV, respectively. This improvement in dielectric and electrical properties at elevated processing temperature is attributed to the reduction in impurity content along with the significant enhancement in sublayer densities and the conductivity contrast driven Maxwell–Wagner interfacial polarisation. Additionally, the devices fabricated at 300 °C exhibited a higher capacitance density of ∼22.87 fF μm⁻², a low equivalent oxide thickness of ∼1.51 nm, and a low leakage current density of ∼10⁻⁷ A cm⁻² (at 1 V bias), making this nanolaminate a promising material for high-density energy storage applications. These findings highlight the ALD process temperature assisted growth chemistry of Al₂O₃/TiO₂ nanolaminates for superior dielectric performance and multifaceted applications.

Enhanced interface confined carrier relaxation and transport in an Al ₂ O ₃ /TiO ₂ nanolaminate, from a suitable combination of sublayer and cap layer thicknesses, is promising for high density energy storage applications.

Maxwell–Wagner relaxation dominated Al2O3/TiO2 nanolaminates (ATA NLs) have recently demonstrated their potential for high-density energy storage applications. In this report, we have unraveled the defect-mediated transport mechanisms prevailing in Al2O3/TiO2 sub-nanometric laminates. Temperature-dependent ac conductivity measurements revealed the signature of small polaron hopping in TiO2 active layers and trap-assisted tunneling transport through Al2O3 barrier layers, which was corroborated by resonant photoelectron spectroscopy and temperature-dependent current–voltage measurement. The polaronic defect states, found ∼1 eV below the Fermi level, served as the hopping centers and leakage paths for current. The signature of quantum tunneling transport and the negative differential conductance observed toward higher electric field was attributed to the splitting of delocalized minibands. These transport properties of Al2O3/TiO2 nanolaminates will help in tailoring these materials for next-generation storage capacitors.