Atomic-Scale Modification of Oxidation Phenomena on the Ge(100) Surface by Si Alloying

Abstract

Properties of Ge oxides are significantly different from those of widely used Si oxides. For example, the instability of GeO x at device junctions causes electronic defect levels that degrade the performance of Ge-containing devices (e.g., transistors and infrared detectors). Therefore, the passivating Si layers have been commonly used at Ge interfaces to reduce the effects of Ge oxide instability and mimic the successful strategy of Si oxidation. To contribute to the atomic-scale knowledge and control of oxidation of such Si-alloyed Ge interfaces (O/Si/Ge), we present a synchrotron radiation core-level study of O/Si/Ge, which is combined with scanning probe microscopy measurements. The oxidation processes and electronic properties of O/Si/Ge(100) are examined as functions of Si amount and oxidation doses. In particular, the incorporation of Si into Ge is shown to cause the strengthening of Ge–O bonds and the increase of incorporated oxygen amount in oxide/Ge junctions, supporting that the method is useful to decrease the defect-level densities.

Theoretical investigation of octahedral tilting and bandgap non‐linearity in monolayer Ruddlesden‐Popper A 2 Pb 1‐x Ge x I 4 perovskites

“…Several stabilization routes, adopted to control alarming Sn 2+ oxidization to the tetravalent state, are also anticipated to prevent Ge 2+ oxidization. The Ge‐interfaces are passivated by Si‐alloying while it strengthens the Ge‐O bonds hence controls the Ge 2+ oxidation 35 …”

“…The Ge-interfaces are passivated by Si-alloying while it strengthens the Ge-O bonds hence controls the Ge 2+ oxidation. 35 Another effective stabilization scheme is by using mixed or double cation doping as recently Wang et al 36 have reduced 97.3% of Pb-content in CsPb 1Àx Ge x Br 3 perovskites with enhanced photovoltaic performance and phase stability. Ge-based perovskites 37 are currently less explored 38 but exhibit comparable photovoltaic properties with anionic conduction band and cationic valence band dominance.…”