Deep Ultraviolet Optical Anisotropy of β-Gallium Oxide Thin Films

Area of Science:

• Materials Science
• Optoelectronics
• Solid State Physics

Background:

• Beta-gallium oxide (β-Ga2O3) is an ultrawide bandgap semiconductor.
• Its monoclinic crystal structure leads to optical anisotropy.
• This anisotropy is crucial for deep ultraviolet (DUV) optoelectronic applications.

Purpose of the Study:

• Investigate the optical properties of β-Ga2O3 thin films.
• Examine the influence of crystallographic orientation of sapphire substrates on optical anisotropy.
• Explore potential DUV optical applications.

Main Methods:

• Pulsed laser deposition (PLD) for growing β-Ga2O3 thin films.
• Growth on sapphire substrates with different crystallographic orientations (r-cut and c-cut).
• Reflectance and Raman spectroscopy to determine in-plane polarization anisotropy.

Main Results:

• Significant in-plane polarization anisotropy observed in β-Ga2O3 films on r-cut sapphire.
• Isotropic optical properties observed in β-Ga2O3 films on c-cut sapphire.
• Demonstrated dependence of optical properties on substrate orientation.

Conclusions:

• The crystallographic orientation of sapphire substrates significantly impacts the optical anisotropy of β-Ga2O3 thin films.
• Tailoring substrate orientation offers a method to control optical properties for DUV devices.
• β-Ga2O3 films show promise for polarization-dependent DUV optical applications.