Investigations on resonant tunneling in III-V heterostructures

We present data obtained on a set of symmetric GaAs/AlGaAs double-barrier quantum-well structures in which the thickness of the AlGaAs barriers has been systematically varied from 31 to 7.5 nm. Low-temperature I(V) characteristics, temperature dependencies, and magnetotunneling have been investigated. Our data suggest a dominance of sequential tunneling processes in the range investigated and point to interface roughness in the well as the possible cause for the large valley currents. Our best devices exhibit a current peak-to-valley ratio of about 20.