MOVPE Growth of High Quality Cubic GaN on GaAs: The Role of Growth Rates

Cubic GaN (c-GaN) layers are grown on GaAs(001) substrates by metalorganic vapor phase epitaxy (MOVPE). To attain high quality c-GaN, we investigate MOVPE growth conditions, particularly focusing on growth rates. As a result, it is found that by increasing the growth rate from 0.35 to 1.05 μm/h, the temperature region where the c-GaN composition reached its maximum (90%) is shifted from (700 to 800) °C towards (850 to 900) °C. This phenomenon is interpreted in terms of the lateral growth rate. It is also revealed that c-GaN with superior optical and electrical properties, that is, excitonic emission and high resistivity, cannot be realized without increasing the growth rate.