فهرست نشریات علمی دسترسی آزاد ایران

This study successfully investigated the structural, morphological, and optical tunability of Germanium Dioxide (GeO2) thin films for potential optoelectronic applications. The films were prepared on Silicon (Si) substrates at ambient temperature using the Pulsed Laser Deposition (PLD) technique, systematically varying the laser energy (200 mJ to 350 mJ) and the SnO2 doping concentration (1 wt% to 908 wt%). High laser energy resulted in a consistent decrease in both AFM grain size (90.01 nm to 65.01 nm) and SEM particle size (58.68 nm to 22.24 nm), while simultaneously causing an increase in RMS roughness (15.6 nm to 25.1 nm) and widening the direct band gap (Eg) (3.55 eV to 3.65 eV). Conversely, SnO2 doping dramatically modifies the surface morphology, causing a consistent increase in AFM grain size and RMS roughness (up to 105.34 nm and 60.4 nm respectively), while the SEM particle size exhibited a non-monotonic trend, achieving the minimum size (18.73 nm) at 5 wt%. Optically, the SnO2 dopant caused a complex shift in Eg, with an initial widening to a maximum of 3.65 eV at 2 wt% followed by Eg narrowing to a minimum of 3.40 eV at 5 wt%. UV absorption consistently peaked at 290 nm and its magnitude generally increased with both higher laser energy and higher doping. The PLD method provides effective dual control: high laser energy enhances structural quality and Eg widening, while SnO2 doping offers fine-tuning, particularly by introducing electronic effects that cause band gap narrowing at higher concentrations.