Dimensional Transition of GaAs from Three to Two Dimension

Controlling the size of semiconductor materials can lead to the change of quantum confinement, i.e., the dimensional transition. Notably, electrical measurements show that the dark current of GaAs with thicknesses of 20 nm and 40 nm is smaller than that of GaAs with a thickness of 60 nm under a bias below 1.5 V, which is interesting and different from the current change with thickness in GaAs bulk materials. However, what dictates this result? Here, an interesting method to study the dimensional transition point has been proposed. It is found that electrons transportation is dominated by dimension effect (DE) in low-dimensional systems and the thickness effect (TE) in bulk materials. Moreover, the external voltage affects DE. The proposed theory is in good agreement with the experimental results.