Structural and Optical Characterization of Non-Polar GaN/AlN Quantum Wells

We have successfully grown non-polar GaN/AlN multiple quantum wells by plasma-assisted molecular beam epitaxy on R-plane sapphire substrates. X-ray diffraction and selected area diffraction data show that the III-nitride epilayers are oriented in the [11 20] direction with the [0001] axis lying in the plane of the substrate. The 18 Angstrom GaN quantum wells exhibit luminescence at 326 nm which is in agreement with the transition energy calculated using a flat band model, i.e., without the presence of a built-in electric field.