Ultrathin-barrier AlN/GaN heterostructures grown by rf plasma-assisted molecular beam epitaxy on freestanding GaN substrates

Storm, D. F., Deen, D. A., Katzer, D. S., Meyer, D. J., Binari, S. C., Gougousi, T., ... Smith, D. J. (2013). Ultrathin-barrier AlN/GaN heterostructures grown by rf plasma-assisted molecular beam epitaxy on freestanding GaN substrates. Journal of Crystal Growth, 380, 14-17. DOI: 10.1016/j.jcrysgro.2013.05.029

We report the structural and electrical properties of ultrathin-barrier AlN/GaN heterostructures grown on freestanding GaN substrates by rf plasma-assisted molecular beam epitaxy. Structures with barrier thicknesses between 1.5 nm and 7.5 nm were grown and characterized. We observe that AlN/GaN structures with barriers of 3.0 nm exhibit the highest Hall mobility, approximately 1700 cm(2)/Vs. Furthermore, the Hall mobility is much diminished in heterostructures with AlN barriers thicker than 45 am, coincident with the onset of strain relaxation. Published by Elsevier B.V.