THEORETICAL AND EXPERIMENTAL STUDY OF PEROVSKITE AND III-V SEMICONDUCTORS

Abstract

Density functional theory (DFT) calculation is a powerful tool for studying the electronic structures. We employed DFT calculations to study the perovskite and III-V semiconductors. Chapter 3 estimated the quantum confinement for CsPbBr3 perovskite NCs. The DFT study was combined with TEM to explore the growing mechanism of the NCs. Chapter 4 focused on the (001) surface of CsPbBrxI3-x. We revealed the origin of the ligand enhanced stability: the energy level of the anti-bonding VBM on the surface was lowered by the ligand-induced relaxation. The passivated surfaces had higher stability for oxidation than the bare surfaces due to the deep localized VBM. In Chapter 5 proposed a novel model for InAs-InP-ZnSe-ZnS. The partial densities were employed to determine a quasi-type II alignment of the NCs. The bandgap energy shift agreed with the experimentally measured PL. Our model showed remarkable portability and can be extended to other core-shell systems.