Analyzing the opto electronic dynamics of ZnO/CeO₂ nano composites at higher annealing temperatures (600 °C and 900 °C)

Abstract This study investigates the comparative analysis for the optoelectronic properties of zinc oxide/cerium oxide (ZnO/CeO 2 ) thin films prepared by e-beam evaporation and sputter deposition. A 180 nm cerium oxide (CeO 2 ) layer was deposited on a 370-micron silicon substrate, followed by a 150 nm zinc oxide (ZnO) layer. The bilayer films were annealed at 600 °C and 900 °C. X-ray diffraction (XRD) revealed improved crystallinity post-annealing, while scanning electron microscopy (SEM) showed morphological changes from nano fibers to nano sheets for e-beam evaporation and nano spheres for sputter deposition. The ZnO band gap decreased from 3.00 eV to 2.1 eV with annealing for e-beam evaporation and 2.70 eV to 2.10 eV with annealing for sputter deposition, showing enhanced conductivity in both un annealed and annealed films. Hall Effect measurements indicated increased mobility and resistance with higher annealing temperatures i.e. conductivity changed from 8.97 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">×</mml:mi> </mml:math> 10 −3 to 6.68 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">×</mml:mi> </mml:math> 10 −1 for e-beam evaporation and 4.45 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">×</mml:mi> </mml:math> 10 −1 to 6.18 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">×</mml:mi> </mml:math> 10 −1 for sputter deposition. The study demonstrates the tailored optoelectronic characteristics of ZnO/CeO 2 thin films, with implications for materials research and electronic devices.