Richard W. Streater

Optical quality of InGaAsN/GaAs

Bulk layers of GaAsN and InGaAsN and GaAs/InGaAsN/GaAs quantum wells with nitrogen concentration of about 1% have been grown by bas source molecular beam epitaxy with a radio frequency discharge N source. The material has been characterized by X-ray diffraction, secondary ion mass spectrometry, photoluminescence (PL) and Hall effect with the intention of understanding and overcoming the mechanism responsible for the diminished optical quality of the nitride material relative to the material without nitrogen. The PL yield of the InGaAsN quantum wells can be significantly improved by optimized annealing treatment, although the quality is currently still inferior to the nitrogen-free material. Hall effect measurements on the nitride material indicate the presence of states in the bandgap acting as hole traps and electron traps; it is expected that these states act as the non-radiative recombination centres responsible for the reduced optical quality.