Band Offsets from Angle-Resolved Valence Band Photoemission Spectroscopy

Dataset: ARPES and XPS raw data used for our published work: P. Constantinou, et al. “Band Offsets from Angle‐Resolved Valence Band Photoemission Spectroscopy.” Adv. Mater. Interfaces (2025): e00340. Abstract: The conduction band offset, ϕ0, at semiconductor surfaces and interfaces is one of the most important parameters for modern quantum devices, many of which take advantage of proximity-induced collective states such as superconductivity and magnetism. Nonetheless, it remains difficult to measure experimentally with high accuracy. Recently, a method combining angle-resolved conductions band and core-level photoelectron spectroscopy has been shown to yield band offsets that align well with a direct measurement of the quantized subband energies of the conduction band. Because this method is limited to semiconductor surfaces with native accumulation layers, we introduce here a more general approach for band offset determination from angle-resolved valence band (VB) photoemission spectra that is applicable to all semiconductor surfaces and interfaces. The key idea is to identify the top of the valence band from fitting to a summation of the contributions from individual layers to the VB signal at the Γ-point of the Brillouin zone, rather than from a conventional leading-edge determination for the observed valence band signal. Our results matches the offset extracted from the quantized conduction subbands on InAs(111) surfaces, with an average deviation of 51 meV, which is well below their deviation (of order 185 meV) from the extracted from the conventional leading-edge method. We use our new approach to extract band offsets for a series of systems relevant for topological superconductivity, namely InSb(110)/vacuum (ϕ0 = 5 ± 21 meV), oxidized InSb(110) (ϕ0 = 65 ± 69 meV), hydrogen cleaned InSb(110) (ϕ0 = 40 ± 63 meV), and the semiconductor/superconductor interface InSb(110)/Al (ϕ0 = 74 ± 13 meV), all of which lack an observable accumulation layer with angle-resolved photoemission spectroscopy.