Perez-Tomas, A.; Fontsere, A.; Llobet, J.; Placidi, M.; Rennesson, S.; Baron, N.; Chenot, S.; Moreno, J.C.; Cordier, Y. "Analysis of the AlGaN/GaN vertical bulk current on Si, sapphire, and free-standing GaN substrates" Journal of Applied Physics 113, 17, pp. - 2013 DOI: 10.1063/1.4803130