2023/12/01 by Jiarui Gong, Gong, Jiarui, Jie Zhou +25 · 1 citation
Energy · Materials Science · #Advanced Photocatalysis Techniques #FOS: Physical sciences #Ga2O3 and related materials #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2312.00771
openalex publication_date 2023/12/01 · openalex created_date 2023/12/05 · openalex updated_date 2026/07/28
Beta-phase gallium oxide (β-Ga2O3) research has gained accelerated pace due to its superiorly large bandgap and commercial availability of large-diameter native substrates. However, the high acceptor activation energy obstructs the development of homojunction bipolar devices employing β-Ga2O3. The recently demonstrated semiconductor grafting technique provides an alternative and viable approach towards lattice-mismatched β-Ga2O3-based p-n heterojunctions with high quality interfaces. Understanding and quantitatively characterizing the band alignment of the grafted heterojunctions is crucial for future bipolar device development employing the grafting method. In this work, we present a systematic study of the band alignment in the grafted monocrystalline Si/β-Ga2O3 heterostructure by employing X-ray photoelectron spectroscopy (XPS). The core level peaks and valence band spectra of the Si, β-Ga2O3, and the grafted heterojunction were carefully obtained and analyzed. The band diagrams of the Si/β-Ga2O3 heterostructure were constructed using two individual methods, the core level peak method and the valence band spectrum method, by utilizing the different portions of the measured data. The reconstructed band alignments of the Si/β-Ga2O3 heterostructure using the two different methods are identical within the error range. The band alignment is also consistent with the prediction from the electron affinity values of Si and β-Ga2O3. The study suggests that the interface defect density in grafted Si/β-Ga2O3 heterostructure is at a sufficiently low level such that Fermi level pinning at the interface has been completely avoided and the universal electron affinity rule can be safely employed to construct the band diagrams of grafted monocrystalline Si/β-Ga2O3 heterostructures.