Non-resonant tunneling in single pairs of vertically stacked asymmetric InP/GaInP quantum dots

In this work, single vertically stacked asymmetric InP/GaInP quantum dot (QD) pairs that are separated by different barrier widths have been investigated. We have found that for large (20 nm) inter-dot distances no tunneling is possible, that for medium spacer widths (10 nm) electrons can tunnel from the large dot to the small dot, and that finally, for very small (5 nm) barriers both electrons and holes can tunnel. We have simulated our results using a rate-equation model and have found a good agreement between simulation and experiment.