Current-voltage and capacitance-voltage characteristics of an n-GaN/n(
+)-GaAs substrate heterojunction have been measured over the temperatu
re range from 120 to 360 K. It was found that, depending on the GaAs s
ubstrate temperature, the heterojunction behaves either as a Sack-to-b
ack diodes structure or as a metal-insulator-semiconductor (MIS) struc
ture. From the reverse bias saturation currents, an activation energy
was estimated and was found to be 0.25 and 0.16 eV for the samples whi
ch behaved as MIS structures. (C) 1998 Published by Elsevier Science B
.V. All rights reserved.