Growth and characterization of (Ga1-xGdx)2O3 by pulsed laser deposition for wide bandgap applications

Thin film wide bandgap Ga2O3 based alloys are important for applications in high power electronic, gate dielectric, deep UV photonics, spintronics and nuclear detectors. Epitaxial (Ga1-xGdx)(2)O-3 thin films with varied x were successfully grown on Al2O3 (0001) substrates to tune the materials properties using variations in the growth parameters. High growth temperatures favor the formation of the monoclinic beta-(Ga1-xGdx)(2)O-3 phase; the higher the Gd composition, the greater the growth temperature required for high quality crystalline thin films. Incorporation of Gd into Ga2O3 crystal expands the crystal lattice causing peak shift toward lower angle. UV-vis measurements demonstrate a slight red shift of the bandgap (4.99-4.82 eV) in comparison with the pure beta-Ga2O3. Extracted refractive index from surface ellipsometry were in the range of 1.86-1.92. XPS spectroscopy confirmed the presence of Gd3+ oxidation states. Current voltage measurements demonstrate Gd doping increases the resistivity of the samples. Finally, our findings are confirmed by density functional study.

Automated summary

Thin film wide bandgap Ga2O3 based alloys have important applications in various fields such as high power electronics, deep UV photonics, and spintronics. This study successfully grew epitaxial (Ga1-xGdx)(2)O-3 thin films on Al2O3 substrates with varied compositions, and the material properties could be tuned by adjusting the growth parameters. The results showed that higher growth temperatures favored the formation of the desired phase, and the incorporation of Gd into Ga2O3 caused lattice expansion and a red shift in bandgap. XPS spectroscopy confirmed the presence of Gd3+ oxidation states, and current voltage measurements demonstrated an increase in resistivity with Gd doping. These findings were further supported by density functional theory calculations.