High-electron-mobility $AlGaN∕GaN$ heterostructures grown on Si(001) by molecular-beam epitaxy

The growth of $AlGaN∕GaN$ heterostructure on Si (001) substrates by molecular-beam epitaxy using ammonia as nitrogen precursor is reported. The structural, optical, and electrical properties of such heterostructures are assessed. It is shown that a two-dimensional electron gas is formed at the $Al0.23Ga0.77N∕GaN$ interface. This type of heterostructure exhibits a sheet carrier density of $4.2×1012cm−2$ with a mobility of $730cm2∕Vs$ at room temperature. Preliminary results concerning high-electron-mobility-transistor static characteristics are presented.