Band gap shift in the GaN/AlN multilayers on the mesh-patterned Si(111)

The band gap shift in the 80x80 mu m(2) crack-free GaN/AlN multilayers on the mesh-patterned Si(111) has been characterized by cathodoluminescence (CL) and Raman techniques. The GaN band gap derived from CL spectra depends on the spatial point inside a mesh, which changes from 3.413 eV (at center) to 3.418 eV (at edge) and to 3.426 eV (at corner). The band gap shift is attributed to the variation of tensile stress inside the mesh, confirmed by Raman mapping. The shift of GaN band gap per unit stress is determined to be 0.03 eV/GPa. (c) 2006 American Institute of Physics.