POLARITY RELATED PROBLEMS IN GROWTH OF GAN HOMOEPITAXIAL LAYERS

Homoepitaxial layers of GaN were grown by metalorganic chemical vapour deposition on single crystals obtained by high-pressure, high-tempera ture technology. For each metalorganic chemical vapour deposition run, four samples were placed, (00.1) and (00.1) faces of the Mg-doped ins ulating and undoped highly conductive substrates. The layers were exam ined using X-ray diffraction, photoluminescence and far-infrared refle ctivity. It was found that the (00.1) easier incorporates donors resul ting in higher free-electron concentrations in the layers grown on the se sides of the crystals, both, undoped and Mg-doped.