Intersubband Transitions in GaNZAl0.5Ga0.5N Quantum Wells on a-Plane and m-Plane GaN Substrates

We experimentally characterize mid-infrared intersubband transitions in identical Al 0.5 Ga 0.5 N/GaN heterostructures grown on a- and m-plane GaN substrates. The absorption peaks of the m-plane samples are 10 to 40% narrower than that of the a-plane samples.