High-quality AlGaN/GaN superlattices for near- and mid-infrared intersubband transitions

A pulsed layer-by-layer deposition (PLLD) technique possessing triple growth rates compared to conventional growth techniques is developed by metal-organic chemical vapor deposition to realize high-quality high-aluminum content ordered Al _XGa _(1-X)N (0.5<X). X-ray diffraction, photoluminescence, and transmission measurements are employed to demonstrate control over aluminum content, structural uniformity, and optical quality in the ordered Al _XGa _(1-X)N. To show the feasibility of device applications, Al _XGa _(1-X)N as barrier and GaN as well are employed in superlattices demonstrating intersubband transitions in the infrared regime. Effects of well width and barrier aluminum content on the intersubband absorption characteristics are reported.