Computing with DFT Band Offsets at Semiconductor Interfaces: A Comparison of Two Methods

Abstract

Two DFT-based methods using hybrid functionals and plane-averaged profiles of the Hartree potential (individual slabs versus vacuum and alternating slabs of both materials), which are frequently used to predict or estimate the offset between bands at interfaces between two semiconductors, are analyzed in the present work. These methods are compared using several very different semiconductor pairs, and the conclusions about the advantages of each method are discussed. Overall, the alternating slabs method is recommended in those cases where epitaxial mismatch does not represent a significant problem.

Band offset in semiconductor heterojunctions

“…The band offsets of ZnSe/Ge, ZnSe/GaAs, and SrTiO 3 /TiO 2 significantly deviate by few decimals of an eV from the reference values. This sizeable discrepancy between band offsets obtained by ASJ and IU methods are in line with a recent study by Conesa showing that for ZnS/CuGaS 2 and diamond/α-tin interfaces differences up to 0.3 eV were found [120].…”

WO3/BiVO4 Photoanodes: Facets Matching at the Heterojunction and BiVO4 Layer Thickness Effects

“…This 0.3 eV band offset increase is similar to that obtained in oxide interfaces. 72 The convergence of the results as a function of the BiVO 4 layer thickness was investigated in order to exclude quantum confinement effects. 73 We simulated two additional interface models (full data in the Supporting Information) having different BiVO 4 thicknesses, while the thickness of WO 3 was kept fixed to 1.6 nm since it already leads to converged properties.…”

“…The formation of the interface leads to a ∼0.3 eV enhancement of the band offsets, which is expected to improve the driving force of the electron migration toward WO 3 and holes migration toward BiVO 4 . This 0.3 eV band offset increase is similar to that obtained in oxide interfaces …”

InterMat: accelerating band offset prediction in semiconductor interfaces with DFT and deep learning

“…This can be done in either of the following two ways: 1) by attaching the two surface slabs together without vacuum padding, creating a superlattice or alternating slab junction (ASJ) structure, or 2) by attaching the two surface slabs with vacuum padding, creating a surface terminated junction (SJT) structure. We have focused on the ASJ approach 16,80 . After obtaining surface slab structures as discussed in the previous section, we generate the interfaces following the Zur et.…”