P- and N-type doping of GaN and AlGaN epitaxial layers grown by metalorganic chemical vapor deposition

Mg- and Si-doped GaN and AlGaN films were grown by metalorganic chemical vapor deposition and characterized by room-temperature photoluminescence and Hall-effect measurements. We show that the p-type carrier concentration resulting from Mg incorporation in GaN:Mg films exhibits a nonlinear dependence both on growth temperature and growth pressure. For GaN and AlGaN, n-type doping due to Si incorporation was found to be a linear function of the silane molar flow. Mg-doped GaN layers with 300K hole concentrations p similar to 2 x 10(18) cm(-3) and Si-doped GaN films with electron concentrations n similar to 1 x 10(19) cm(-3) have been grown. N-type Al0.10Ga0.90N:Si films with resistivities as low as p similar to 6.6 x 10(-3) Omega-cm have been measured.