Engineering the Interfacial Electronic Structure of Epitaxial Ge/AlAs(001) Heterointerfaces via Substitutional Boron Incorporation: The Roles of Doping and Interface Stoichiometry

Abstract

A joint experimental and theoretical framework for the decoupling of boron (B) doping and stoichiometric-induced modifications to the structural properties and electronic band structure of germanium (Ge)/AlAs(001) heterostructures is presented. The effect of B-induced stress on nearest-neighbor Ge bonds is quantified via X-ray diffractometry and Raman spectroscopic analysis and subsequently interpreted through the lens of density functional perturbation theory. Similarly, experimental determination of the energy band alignment at the p-type Ge:B/AlAs heterointerface is understood using a density functional theory approach to model the influence of heterointerface stoichiometry and interatomic bonding between group IV and III–V interfacial atoms on the valence and conduction band discontinuities. The modeled two monolayer interatomic diffusion at the Ge/AlAs heterointerface is confirmed via atom probe tomography analysis, demonstrating a ∼6 Å interfacial width. These results present a unified picture of the Ge:B/AlAs(001) material system, highlighting the influence of B on its structural and electronic properties, and provide a path for the engineering of such heterointerfaces through high concentration dopant incorporation within the overlying Ge epilayer.

High carrier lifetimes in epitaxial germanium–tin/Al(In)As heterostructures with variable tin compositions

“…1(b) shows the schematic of the band alignment of Ge 1− y Sn y /In x Al 1− x As heterostructures with selected Sn compositions from 0 to 15%. The band alignments of the starting Ge/AlAs 56 and ε-Ge/In 0.26 Al 0.74 As 52 heterostructures, experimentally demonstrated via X-ray photoelectron spectroscopy, were used. Moreover, the change in Δ E V was relatively insignificant compared to Δ E C with increasing In compositions in In x Al 1− x As.…”

Mapping the Interfacial Electronic Structure of Strain-Engineered Epitaxial Germanium Grown on InxAl1–xAs Stressors

“…It has been well established that atomic interdiffusion across semiconductor heterojunctions is capable of quantitatively modifying the heterointerfacial energy band alignment, − wherein variations in the local bonding environment at the interface can correspond to a significant range of possible interfacial electronic configurations. This is particularly true for IV/III–V heterointerfaces, more specifically, Ge/III–V heterointerfaces, which have been predicted to exhibit either staggered (type I) or straddling (type II) interfacial electronic structures depending on the heterointerfacial stochiometry. , Despite this remarkable result, relatively few studies have been reported on the experimental ,, or theoretical , investigation of the heterovalent Ge/III–V interface. In particular, the first-principles-based systematic investigation of the heterovalent ε-Ge/In x A l– x As interface by Greene-Diniz et al remains the only reported theoretical inquiry into the ε-Ge/In x Al 1– x As interfacial electronic structure, that is, the same property of the ε-Ge/In x Al 1– x As material system studied in this work.…”

Atomic layer deposited tantalum silicate on crystallographically-oriented epitaxial germanium: interface chemistry and band alignment

“…, “bulk-like” Ge. Eqn (1), following the methodology developed by Kraut et al 75 as utilized in previous studies, 50,54,56,59,76–80 was used to determine the Δ E V :where is the BE separation between the Ta (Ge) 4d 5/2 (2p 3/2 ) state and the VBM of the respective material and is the BE separation between the Ta 4d 5/2 and Ge 2p 3/2 states measured at the interface. Similarly, the conduction band offset (Δ E C ) can be determined using the following relation:where and E Ge g are the bandgaps of TaSiO x and Ge, respectively, and Δ E V is the measured valence band offset.…”

“…To evaluate the valence band discontinuity (DE V ) at the TaSiO x dielectric/semiconductor interface, XPS spectra were recorded from: (i) nominally 5 nm (Ta 2 O 5 ) 1Àx (SiO 2 ) x on crystallographicallyoriented (001)Ge, (110)Ge, and (111)Ge, i.e., ''bulk-like'' TaSiO x ; (ii) nominally 1.5 nm (Ta 2 O 5 ) 1Àx (SiO 2 ) x on crystallographicallyoriented (001)Ge, (110)Ge, and (111)Ge, i.e., the oxide/semiconductor interface; and (iii), the surface of the as-grown (001)Ge, (110)Ge, and (111)Ge thin-films integrated on GaAs, i.e., ''bulklike'' Ge. Eqn (1), following the methodology developed by Kraut et al 75 as utilized in previous studies, 50,54,56,59,[76][77][78][79][80] was used to determine the DE V :…”

“…Lastly, as discussed in the Experiments section, we note that statistical deviation in the Au 4f 7/2 CL BE of a Au standard was utilized in the derivation of a AE0.04 eV experimental uncertainty for this work, from which successive uncertainty was estimated using a root-sum-square approach. [78][79][80] B.1. Energy band alignment at the TaSiO x /(001)Ge heterointerface.…”