Selective growth of GaN/AlGaN microstructures by metalorganic vapor phase epitaxy

A GaN/AlGaN double heterostructure was fabricated on the (1 (1) over bar 01 ) facets of a GaN triangular structure prepared by selective area growth by metalorganic vapor phase epitaxy. The photoluminescence (PL) and cathode l uminescence (CL) spectra were investigated to characterize the structure. I t was found that the PL peak wavelength due to the GaN quantum well is depe ndent on the well thickness, However. the Al composition of the AlGaN layer is dependent on the position on the (1 (1) over bar 01) facet. The anomalo us gradient of the composition is attributed to the difference in the diffu sion coefficients of At and Ga on the surface.