Then‐type doping of GaN by organometallic vapor phase epitaxy using Si2H6on sapphire has been demonstrated. The electron concentration depended linearly on Si2H6to trimethylgallium mole fraction ratio. State‐of‐the‐art values of 300 K electron mobility were obtained for electron concentrations from 1×1017–4×1019/cm3with no apparent increase in compensation at either the lowest or highest concentrations studied. Electron concentrations obtained using a given concentration of disilane were constant with growth temperature in the range 980–1040 °C. ©1995 American Institute of Physics.