Minority electron transport anisotropy in p-type AlxGa1-xN/GaN superlattices

The minority electron diffusion length, L, in Mg-doped molecular beam epita xy (MBE) grown p-type AlxGa1-xN/GaN superlattices with aluminum content x = 0.1 and 0.2 was measured perpendicular and parallel to the superlattice pl anes by the electron beam induced current (EBIC) technique. A large anisotr opy in the transport properties was observed with the effect varying from 1 : 3 to 1 : 6. We attribute an experimentally observed diffusion length ani sotropy to minority electron scattering during transport across the potenti al barriers of the superlattice. Reference p-GaN samples were also investig ated, and the diffusion length was observed to be isotropic in both metal o rganic chemical vapor deposition (MOCVD) (L = 0.5 mum) and MBE (L = 0.27 mu m) grown samples.