Ti Alloyed α-Ga₂O₃: Route towards Wide Band Gap Engineering.

Area of Science:

• Materials Science
• Semiconductor Physics
• Thin Film Technology

Background:

• Gallium oxide (Ga2O3) is a wide band gap semiconductor with applications in electronics and optoelectronics.
• Modifying the band gap of Ga2O3 is crucial for tuning its optical properties, particularly for solar-blind photodetectors.

Purpose of the Study:

• To investigate the suitability of titanium (Ti) as a band gap modifier for α-Ga2O3.
• To explore the relationship between Ti composition, crystallinity, and band gap in (Ti,Ga)2O3 alloy films.

Main Methods:

• Synthesis of (Ti,Ga)2O3 films using atomic layer deposition (ALD) on sapphire substrates.
• Characterization of film crystallinity and band gap as a function of Ti composition (x).

Main Results:

• High-quality α-(Ti_xGa_{1-x})2O3 films were deposited with Ti concentrations up to x = 3.7%.
• The corundum phase was maintained up to x = 5.3% Ti, with higher concentrations resulting in amorphous films.
• A band gap variation of approximately 270 meV was observed across the crystalline corundum phase films (0% ≤ x ≤ 5.3%).

Conclusions:

• Low fractions of Ti can be incorporated into α-Ga2O3 while maintaining crystallinity, leading to band gap modification.
• These findings show promise for band gap engineering of α-Ga2O3.
• The study highlights potential for developing wavelength-specific solar-blind photodetectors based on Ti-modified α-Ga2O3.