Wurtzite GaN epitaxial growth on a Si(001) substrate using γ-Al2O3 as an intermediate layer

Wurtzite GaN films have been grown on (001) Si substrates using $\mathrm{\gamma -}{\mathrm{Al}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ as an intermediate layer by low pressure $\text{(∼76\hspace{0.17em}}\mathrm{Torr})$ metalorganic chemical vapor deposition. Reflection high energy electron diffraction and double crystal x-ray diffraction measurements revealed that the thin $\mathrm{\gamma -}{\mathrm{Al}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ layer of “compliant” character was an effective intermediate layer for the GaN film grown epitaxially on Si. The narrowest linewidth of the x-ray rocking curve for (0002) diffraction of the 1.3 μm GaN sample was 54 arcmin. The orientation relationship of ${\mathrm{GaN/\gamma -Al}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}\mathrm{/Si}$ was (0001) GaN‖(001) $\mathrm{\gamma -}{\mathrm{Al}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}\text{‖(001)}$ Si, [11–20] GaN‖[110] $\mathrm{\gamma -}{\mathrm{Al}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}\text{‖[110]}$ Si. The photoluminescence measurement for GaN at room temperature exhibited a near band-edge peak of 365 nm (3.4 eV).