The properties of AlGaN films and AlGaN/GaN heterostructures grown on (11(2)over-bar0) sapphire substrates

Abstract

AlxGa1-xN films and AlxGa1-xN/GaN heterostructures were prepared on the (11 (2) over bar0) sapphire substrates at elevated temperatures by alternate supply of trimethylgallium (TMG)/trimethylaluminum (TMA) and ammonia (NH3) in an inductively heated quartz reactor. X-ray studies reveal the monocrystalline nature of these Al-containing structures. The results of absorption measurements of the AlxGa1-xN films exhibit clear cut-off energies of the films. Based on the investigations of transmission electron microscopy (TEM), AlxGa1-xN films and AlxGa1-xN/GaN structures were found to deposit on the ( 11 (2) over bar0) sapphire substrates with < 0001 >(AlGaN) and <1<(1)over bar>00>(AlGaN) being parallel to < 11 (2) over bar0 >(sapphire) and <1<(1)over bar>00>(sapphire), respectively.