Growth dynamics and optimization of Ga(In)AsN/GaAs towards 1.3 μm and 1.55 μm

It is demonstrated that a nitrogen supply, manifested as both a direct nitrogen beam from a rf-activated plasma source and dispersive nitrogen radicals from the growth-chamber background, is appropriate for the growth of GaAs-based nitrides. The nitrogen incorporation efficiency shows a linear relationship with increasing rf power when the nitrogen is supplied dispersively, and a saturation behavior when the nitrogen is supplied as a direct nitrogen beam. The indium composition causes a decrease in the nitrogen incorporation efficiency, which is suspected to be brought about by the increase of the growth rate due to the indium flux, because our experiments have proven that the nitrogen composition of GaAsN epilayers apparently decreases as the growth rate increases. It is more controllable to fix the indium flux first than to fix the nitrogen source condition, so as to facilitate wavelength control. The temperature window for the growth of quality nitride is concluded to be between 440°C and 500°C. For a quantum well with a certain well width, it is better to add more indium and less nitrogen to reach the desired wavelength in order that the quality of the InGaAs material is kept acceptable.