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HL: Halbleiterphysik

HL 14: Poster I

HL 14.91: Poster

Montag, 24. März 2003, 17:00–19:30, HSZ/P2

Carbon Doping of cubic GaN Under Gallium-rich Growth Conditions — •David Pacheco-Salazar, Stephan Preuss, Martin Lübbers, Jürgen Mimkes, Donat As, and Klaus Lischka — Universität Paderborn, Fakultät für Naturwissenschaften, Department Physik, Warburger Strasse 100, 33095 Paderborn

For the development of electronic and optoelectronic devices, techniques to control the doping process are crucial. The most common impurity to achieve p-type doping is magnesium (Mg), however Mg has a large acceptor ionization energy and shows severe compensation effects. Therefore we investigate the carbon as alternative p-type dopant, whose small ionic radius fits excellently to the nitrogen site. We have grown cubic GaN doped by carbon on a semi-insulating GaAs wafer (3 inchs). Optical microscope, photoluminescence and Hall-effect were used for spatially resolved characterization Measurements by optical microscospe showed that the density of gallium-droplets increases from the center to the border. This implicate a gradient of the Ga-flux over the wafer and ensures Ga-rich growth conditions. Hall measurements carried out at room temperature (RT) gave hole concentrations and hole mobilities as high as 6.1x10¹⁸ cm⁻³ and 23.5 cm²Vs⁻¹, respectively. Photoluminescence measurements at RT showed a clear near band edge luminescence at 3.2 eV and an orange band at about 2.2 eV.