Anisotropy in Electron Mobility and Microstructure of GaN Grown by Metalorganic Vapor Phase Epitaxy

The mobility of the electrons in GaN films grown by metalorganic vapor phase epitaxy has been investigated. It is observed that the mobility is anisotropic with a maximum in 〈101-0〉 direction and a minimum in 〈112-0〉 direction. Microstructure analyses illustrate that the density and distribution of defects in these two directions are different. These results suggest that the anisotropy in electronic mobility is caused by a hexagonally symmetric distribution of defects (grain boundaries and dislocations).