Effect of annealing on β-Ga2O3 film grown by pulsed laser deposition technique

Variation of Band Gap and Lattice Parameters of β−(AlxGa1−x)2O3 Powder Produced by Solution Combustion Synthesis

“…A handful of reports have been published that explore the relationships between alloy composition, crystal phase, and band gap of (Al x Ga 1− x ) 2 O 3 , and the results depend strongly both on fabrication method and on whether the material is a thin film or polycrystalline powder . Cooling from a liquid alloy yields β phase for 0 ≤ x ≤ x o , with mixed α + β reported at x o = 0.67 or x o = 0.80 for alloys precipitated from solution or mixed through grinding, respectively, and α phase for x > x o .…”

“…PLD‐deposition of (Al x Ga 1− x ) 2 O 3 continuous composition spread (CCS) films on [100]–oriented MgO substrates yielded [100]–oriented β‐phase films up to x = 0.5, which transition to [100]–oriented γ ‐phase films at higher x . As an alternate means to fabricate (Al x Ga 1− x ) 2 O 3 alloy films, β‐ phase PLD Ga 2 O 3 films grown on sapphire at 700°C–800°C were postannealed up to 1000°C, where a steady decrease in β‐Ga 2 O 3 lattice parameters as the postannealing temperature increased was interpreted in terms of Al interdiffusion . In contrast to MBE and PLD, mist chemical vapor deposition (mist‐CVD) at 500°C on c ‐plane sapphire led to α‐phase (Al x Ga 1− x ) 2 O 3 films at low x .…”

“…found a monotonic increase in the optical band gap versus x for α‐ phase films grown by mist‐CVD, although the composition was inferred from the position of the (0006) diffraction peak originating in the small fraction of the sample exhibiting crystalline diffraction peaks. Goyal et al . also found an increase in the band gap as Al diffused from sapphire into the β‐Ga 2 O 3 film; however, the nonuniform concentration profile precludes determination of the band gap as a function of x .…”

Mg-doped β-Ga2O3 films with tunable optical band gap prepared on MgO (110) substrates by metal-organic chemical vapor deposition

“…There are many different methods used to synthesize β-Ga 2 O 3 films such as sputtering [9,10], thermal evaporation [11,12], pulsed laser deposition (PLD) [13,14], molecular beam epitaxy (MBE) [3,15] and metal-organic chemical vapor deposition (MOCVD) [16]. The doping of β-Ga 2 O 3 films with different dopants such as Si [17] and Cu [18] has also been reported.…”

Dielectric tensor of monoclinic Ga2O3 single crystals in the spectral range 0.5–8.5 eV

“…From the experimental point of view, there are optical characterizations of thin films by several groups. 8,[14][15][16][17][18][19] However, rotation domains present in the thin films and the inferior crystal structure compared to a single crystal prohibited the determination of the tensor components and only an effective dielectric function was measured. Experiments on single crystals are rare and mainly limited to transmission 6,20 and absorption 6,7,21 measurements.…”