A langasite substrate with a-plane orientation and surface roughness Ra < 0.5 nm is loaded into an OMVPE reactor under nitrogen atmosphere. After purging and pressure reduction to ~70 Torr, the susceptor is heated to 1050°C. Ammonia treatment is performed at 1050°C for 5 min, then temperature is reduced to 530°C. A GaN buffer layer (15 nm) is grown using TMG at 4×10⁻⁵ mol/min for 50 s. Temperature is raised to 1030°C and Si-doped GaN (~3.2 µm, n~2×10¹⁸ cm⁻³) is grown for 35 min. An n-AlxGa₁-xN (x<0.15) graded layer (0.5 µm) is grown by linearly ramping TMAl from 0 to 1×10⁻⁵ mol/min over 5 min. Temperature is reduced to 860°C and InxGa₁-xN/InyGa₁-yN multiple quantum wells are grown by periodically switching TMI between 7×10⁻⁶ mol/min (3 s) and 3×10⁻⁵ mol/min (16 s). Temperature is raised to 1030°C and p-AlGaN and p-GaN contact layers are grown with Cp₂Mg doping to achieve acceptor concentration ~3×10¹⁸ cm⁻³. Dislocation density in resulting heterostructures is less than 5×10⁷ cm⁻². White light chromatic coordinates: X=0.31, Y=0.31.

A langasite substrate with a-plane orientation and surface roughness Ra < 0.5 nm is loaded into an OMVPE reactor under nitrogen atmosphere. After purging and pressure reduction to ~70 Torr, the susceptor is heated to 1050°C. Ammonia treatment is performed at 1050°C for 5 min, then temperature is reduced to 530°C. A GaN buffer layer (15 nm) is grown using TMG at 4×10⁻⁵ mol/min for 50 s. Temperature is raised to 1030°C and Si-doped GaN (~3.2 µm, n~2×10¹⁸ cm⁻³) is grown for 35 min. An n-AlxGa₁-xN (x<0.15) graded layer (0.5 µm) is grown by linearly ramping TMAl from 0 to 1×10⁻⁵ mol/min over 5 min. Temperature is reduced to 860°C and InxGa₁-xN/InyGa₁-yN multiple quantum wells are grown by periodically switching TMI between 7×10⁻⁶ mol/min (3 s) and 3×10⁻⁵ mol/min (16 s). Temperature is raised to 1030°C and p-AlGaN and p-GaN contact layers are grown with Cp₂Mg doping to achieve acceptor concentration ~3×10¹⁸ cm⁻³. Dislocation density in resulting heterostructures is less than 5×10⁷ cm⁻². White light chromatic coordinates: X=0.31, Y=0.31.

A langasite substrate with a-plane orientation and surface roughness Ra < 0.5 nm is loaded into an OMVPE reactor under nitrogen atmosphere. After purging and pressure reduction to ~70 Torr, the susceptor is heated to 1050°C. Ammonia treatment is performed at 1050°C for 5 min, then temperature is reduced to 530°C. A GaN buffer layer (15 nm) is grown using TMG at 4×10⁻⁵ mol/min for 50 s. Temperature is raised to 1030°C and Si-doped GaN (~3.2 µm, n~2×10¹⁸ cm⁻³) is grown for 35 min. An n-AlxGa₁-xN (x<0.15) graded layer (0.5 µm) is grown by linearly ramping TMAl from 0 to 1×10⁻⁵ mol/min over 5 min. Temperature is reduced to 860°C and InxGa₁-xN/InyGa₁-yN multiple quantum wells are grown by periodically switching TMI between 7×10⁻⁶ mol/min (3 s) and 3×10⁻⁵ mol/min (16 s). Temperature is raised to 1030°C and p-AlGaN and p-GaN contact layers are grown with Cp₂Mg doping to achieve acceptor concentration ~3×10¹⁸ cm⁻³. Dislocation density in resulting heterostructures is less than 5×10⁷ cm⁻². White light chromatic coordinates: X=0.31, Y=0.31.

A langasite substrate with a-plane orientation and surface roughness Ra < 0.5 nm is loaded into an OMVPE reactor under nitrogen atmosphere. After purging and pressure reduction to ~70 Torr, the susceptor is heated to 1050°C. Ammonia treatment is performed at 1050°C for 5 min, then temperature is reduced to 530°C. A GaN buffer layer (15 nm) is grown using TMG at 4×10⁻⁵ mol/min for 50 s. Temperature is raised to 1030°C and Si-doped GaN (~3.2 µm, n~2×10¹⁸ cm⁻³) is grown for 35 min. An n-AlxGa₁-xN (x<0.15) graded layer (0.5 µm) is grown by linearly ramping TMAl from 0 to 1×10⁻⁵ mol/min over 5 min. Temperature is reduced to 860°C and InxGa₁-xN/InyGa₁-yN multiple quantum wells are grown by periodically switching TMI between 7×10⁻⁶ mol/min (3 s) and 3×10⁻⁵ mol/min (16 s). Temperature is raised to 1030°C and p-AlGaN and p-GaN contact layers are grown with Cp₂Mg doping to achieve acceptor concentration ~3×10¹⁸ cm⁻³. Dislocation density in resulting heterostructures is less than 5×10⁷ cm⁻². White light chromatic coordinates: X=0.31, Y=0.31.