Carbon as an acceptor in cubic GaN/3C–SiC

✍ Scribed by A. Zado; E. Tschumak; J.W. Gerlach; K. Lischka; D.J. As

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 265 KB
• Volume: 323
• Category: Article
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2010.12.044

✦ Synopsis

We report on carbon doping of cubic GaN by CBr 4 using plasma-assisted molecular beam epitaxy. Cubic GaN:C samples were doped at different CBr 4 beam equivalent pressures between 2 Â 10 À 9 and 6 Â 10 À 6 mbar. The incorporated carbon concentration of up to 1 Â 10 20 cm À 3 was achieved in c-GaN:C as measured by secondary ion mass spectroscopy. The net donor/acceptor concentration was obtained by evaluation of capacitance-voltage data. Capacitance-voltage measurements on nominally undoped cubic GaN showed n-type conductivity. With an increase in CBr 4 flux the conductivity type changed to p-type and for highest CBr 4 flux an acceptor surplus of 1 Â 10 19 cm À 3 was obtained. The electrical properties of the c-GaN:C layers were investigated by current-voltage measurements and a decrease in the serial conductance by two orders of magnitude was demonstrated in c-GaN:C. A blue shift of the 2 K donoracceptor pair luminescence with an increase in carbon concentration was obtained.