Effect of Al mole fraction on structural and electrical properties of AlxGa1−xN/GaN heterostructures grown by plasma-assisted molecular beam epitaxy

▶ The successful growth of AlxGa1−xN thin films on Si (1 1 1) substrate with various Al mole fractions has been obtained. ▶ Structural and morphology studies indicate that relatively larger tensile strain exits in the sample with the smallest Al mole fraction. ▶ A smaller compressive strain and larger grain size appears with Al mole fraction = 0.3. ▶ Strain is relaxed with the highest Al mole fraction sample. ▶ Linear relationship between the barrier height and Al mole fraction has been obtained.