Quantum confinement in group III-V semiconductor 2D nanostructures

In this work we investigate the role of quantum confinement in group III-V semiconductor thin films (2D nanostructures). To this end we have studied the electronic structure of nine materials (AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs and InSb) by means of Density Functional Theory (DFT) calculations using a screened hybrid functional (HSE06). We focus on the structural and electronic properties of bulk and the (110) surfaces, for which we evaluate and rationalize the impact of system size to the band gap and band edge positions. Our results indicate that when the quantum confinement is strong, it mainly affects the position of the Conduction Band Minimum (CBM) of the semiconductor, while the Valence Band Maximum (VBM) is almost insensitive to the system size. The results can be rationalized in terms of electron and hole effective masses. Our conclusions, based on slabs, can be generalized to other cases of quantum confinement such as quantum dots, overcoming the need for an explicit consideration and calculation of the properties of semiconductor nanoparticles.