Conductivity Measurements on GaN Grown by OMVPE and HVPE

ABSTRACTWe report on conductance and cyclotron resonance (CR) experiments on GaN epitaxial films grown by the OMVPE and HVPE techniques. From a precise determination of the electron effective mass the donor binding energy in the effective mass approximation (EMT) is calculated. We obtain 31.7 meV. The transport experiments on the HVPE films show that the conductance is thermally activated with an activation energy of 15 meV in contrast to the OMVPE films which showed temperature independent conductivity for temperatures between 4 and 100 K.