Influence of a piezoelectric field on the electron distribution in a double GaN/Al0.14Ga0.86N heterojunction

C-V profiling of Al0.14Ga0.86N/GaN heterojunctions was performed. It was fo und that a heterojunction with the Al0.14Ga0.86N layer on top increases the electron concentration at the Al0.14Ga0.86N/GaN interface, while the rever sed structure with the GaN layer on top decreases it. In accordance with th is result, an Al0.14Ga0.86N/GaN double heterojunction was found to experien ce a strongly asymmetric electron distribution with an enhancement of the e lectron concentration at the interface closest to the sample surface. This effect is attributed to the presence of a piezoelectric field redistributin g the electrons in the heterostructure. (C) 1999 American Institute of Phys ics. [S0003-6951(99)03825-5].